Abstract: An ophthalmic surgical microscope (100) has a microscope main objective (101) and a viewing beam path (105) which passes through the microscope main objective (101) for visualizing an object region. The ophthalmic surgical microscope (100) includes an OCT-system (140) for recording images of the object region (108). The OCT-system (140) includes an OCT-scanning beam (142) which is guided via a scan mirror arrangement (146) to the object region (108). An optic element (147) is provided between the scan mirror arrangement (146) and the microscope main objective (101). This optic element (147) bundles the OCT-scanning radiation exiting from the scan mirror arrangement (146) and transfers the same into a beam path which passes through the microscope main objective (101). Alternatively or in addition, the ophthalmic surgical microscope (100) includes an ophthalmoscopic magnifier lens (132) which can be pivoted into and out of the viewing beam path (105) and the OCT-scanning beam path (142).

Abstract: A collimated light is used in combination with a compensation element and an aberration-corrected objective with a long working distance to produce a greatly improved fringe contrast in the measurement of a sample surface through a dispersive element. When the dispersive element consists of a fixed cover with substantially consistent characteristics from sample to sample, the compensation element is a plate that matches the optical characteristics of the dispersive element. When the dispersive element varies, the compensation element consists of a variable-thickness transmissive element embodied in a pair of half-cube prisms is adapted to slide along the beam-splitting plane, thereby permitting the adjustment of the optical path-length through the splitter in the reference-beam direction while retaining unchanged the optical path-length in the test-beam direction.

Abstract: Three-dimensional shape measuring instrument (white interferometer) for measuring the three-dimensional shape of an object to be measured by using white interference fringes, which detects the position where the amplitude of the white interference fringes takes on a maximum value with high accuracy in a short calculation processing time. An envelope distribution of the amplitude of the white interference fringes produced by the interference between the returning light from a reference mirror (6) and the returning light from an object (7) to be measured is determined, and an approximate position where the contrast of the white interference fringes is the highest is determined using this envelope distribution.

Abstract: Provided is an optical image measuring apparatus capable of effectively receiving interference light, particularly an alternating current component thereof using a smaller number of photo sensors. The optical image measuring apparatus includes a polarizing plate for converting a light beam from a broad-band light source to linearly polarized light, a half mirror for dividing the light beam into signal light and reference light, a piezoelectric element for vibrating a reference mirror, a wavelength plate for converting the reference light to circularly polarized light, a polarization beam splitter for extracting two different polarized light components from interference light produced from the signal light and the reference light which are superimposed on each other by the half mirror, CCDs for detecting the two different polarized light components, and a signal processing portion for producing an image of an object to be measured based on the detected polarized light components.

Abstract: An optical tomographic apparatus is provided and includes a light source portion, an interferometer, and a signal processing portion. The light source portion including two low coherent light sources capable of simultaneously emitting light having wavelength bands different from each other. The emitted light is divided in two of a light flux irradiated to a subject by a probe and a light flux irradiated to reference mirrors that is divided by a dichroic mirror into light fluxes for respective wavelength bands. The reference light from the reference mirrors is combined with detected light from the subject to provide interference light. An optical detector detects the interference light for respective wavelength bands by a spectroscopic optical system, and a signal processing portion processes the detected light to provide optical tomographic images with regard to different portions of the subject for respective wavelength bands.

Abstract: A partially coherent light beam from a light source is split between a probe light beam toward an observation object and a reference light beam toward a fixed reflective surface. The frequency of the probe light beam is shifted by optical-modulation means. The probe light beam whose frequency has been shifted is swept in a direction of an optical axis and in a direction orthogonal thereto to scan the object two-dimensionally. Reflected light beam from the object is combined with the reference light beam to generate interference light. A detector receives a time-based interference signal from the interference light obtained from the movement of the probe light beam in the direction of the optical axis and the sweeping in the direction orthogonal to the optical axis to derive therefrom reflection intensity data of the object. In such a configuration, the mechanically moving portion is disposed in the probe optical path.

Abstract: A system for forming an anodized coating on at least a portion of a substrate thereby creating an anodized substrate is disclosed. The system includes a bath, a coating thickness monitor, at least one probe and at least one controller. The coating thickness monitor includes at least one radiation source directed at at least a portion of the anodized substrate; at least one probe for capturing at least a portion of the radiation reflected and refracted by the anodized coating on the anodized substrate, the captured radiation being at least a portion of the radiation directed the anodized substrate from the radiation source; and at least one detector in communication with the at least one probe, the at least one detector capable of processing the captured radiation to allow a determination of at least the thickness.

Abstract: A system and method for imaging of a sample, e.g., biological sample, are provided. In particular, at least one source electro-magnetic radiation forwarded to the sample and a reference may be generated. A plurality of detectors may be used, at least one of the detectors capable of detecting a signal associated with a combination of at least one first electro-magnetic radiation received from the sample and at least one second electro-magnetic radiation received from the reference. At least one particular detector may have a particular electrical integration time, and can receive at least a portion of the signal for a time duration which has a first portion with a first power level greater than a predetermined threshold and a second portion immediately preceding or following the first portion. The second portion may have a second power level that is less than the predetermined threshold, and extends for a time period which may be, e.g., approximately more than 10% of the particular electrical integration time.

Abstract: An image data set acquired by an optical coherence tomography (OCT) system is corrected for effects due to motion of the sample. A first set of A-scans is acquired within a time short enough to avoid any significant motion of the sample. A second more extensive set of A-scans is acquired over an overlapping region on the sample. Significant sample motion may occur during acquisition of the second set. A-scans from the first set are matched with A-scans from the second set, based on similarity between the longitudinal optical scattering profiles they contain. Such matched pairs of A-scans are likely to correspond to the same region in the sample. Comparison of the OCT scanner coordinates that produced each A-scan in a matching pair, in conjunction with any shift in the longitudinal scattering profiles between the pair of A-scans, reveals the displacement of the sample between acquisition of the first and second A-scans in the pair.

Abstract: An interferometer system includes an optical radiation source, an optical circulator connected between the optical radiation source and a sample location for transmitting optical radiation from the optical radiation source to the sample location, an output of the optical circulator connected to direct optical radiation to an optical detector. Various embodiments of such a system are possible. A method of performing OCDR or OCT imaging of a sample which involves the steps of: (a) producing low coherence optical radiation; (b) directing at least some of the low coherence optical radiation through an optical circulator to the sample; (c) reflecting at least some of the low coherence optical radiation off of the sample; and (d) detecting at least some of the reflected low coherence optical radiation and producing an electrical signal corresponding thereto.

Abstract: Apparatus, method, logic arrangement and storage medium are provided for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source can be split into N spectral bands. The N spectral bands can be individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band may be detected by a separate photo detector and amplified. For each spectral band, the signal can be band p3 filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is likely reduced by a factor equal to the number of spectral bands, while the signal amplitude can remain the same.

Abstract: A digitized image of an object may include representations of portions of the object that are obscured, occluded or otherwise unobservable. The image may be a multi-dimensional visual representation of dentition. Characteristics of the dentition and its surfaces, contours, and shape may be determined and/or analyzed. A light may be directed toward and reflected from the dentition. The reflected light may be combined with a reference to determine characteristics of the dentition, including obscured areas such as subgingival tissue.

Abstract: Embodiments of the present disclosure provide systems and methods for constructing a profile of sample object. Briefly described, in architecture, one embodiment of the system, among others, can be implemented as follows. An interferometer device is used to collect interference images of a sample object at a sequence of angles around the sample object. Accordingly, a controller device rotates the sample object to enable acquisition of the interference images; and a projection generator produces projections of the sample object from the interference images at the sequence of angles. Further, a tomographic device constructs the profile of the optical device from the projections of the interference images. The profile is capable of characterizing small index variations of less than 1×10?4. Other systems and methods are also included.

Abstract: An optical image measuring apparatus capable of speedily measuring a velocity distribution image of a moving matter.

Abstract: A method for obtaining an image of a tooth obtains an area image of the tooth (20) surface and identifies a region of interest from the area image by positioning a marker (146) on the area image. The marker (146) corresponds to at least a portion of the region of interest and identifies a scanning area. An optical coherence tomography (OCT) image is then obtained over the scanning area.

Abstract: In common path time domain OCT/OCR devices optical radiation from a source is first split into two replicas, which are then delivered to an associated sample by an optical fiber probe. The tip of the optical fiber probe serves as a reference reflector and also serves as a combining element that produces a combination optical radiation by combining an optical radiation returning from the associated sample with a reference optical radiation reflected from the reference reflector. The topology of the devices eliminates the necessity of using Faraday mirrors, and also allows for registering a cross-polarized component of the optical radiation reflected or backscattered from the associated sample, as well as a parallel-polarized component.

Abstract: A complex conjugate ambiguity can be resolved in an Optical Coherence Tomography (OCT) interferogram. A reference light signal is propagated along a reference path. A sample light signal is impinged on a sample reflector. The reference light signal is frequency shifted with respect to the sample light signal to thereby separate a positive and a negative displacement of a complex conjugate component of the OCT interferogram.

Abstract: Apparatus and methods are provided for implementing a full width array material scanning spectrophotometer by integrating a Fabry-Perot cavity filter with a silicon photodetector and a light focusing device (an optical guide or a SELFOC® lens). The material to be scanned is illuminated by a broad band illumination source (white LEDs or a fluorescence light source). The Fabry-Perot cavity gap can be tuned electromechanically to get multiple measurements to resolve the spectral distribution of the transmitted light signal. The array spectrophotometric architecture facilitates an elongated, substantially linear band detection and the associated spectral reconstruction technique resolves spectral distribution in the presence of multiple resonant peaks.

Abstract: One embodiment of the present invention is a method for suppressing artifacts in frequency-domain OCT images, which method includes (a) providing sample and reference paths with a significant difference in their chromatic dispersion (b) correcting for the effects of the mismatch in chromatic dispersion, for the purpose of making artifacts in the OCT image readily distinguishable from the desired image.

Abstract: An optical coherence tomography (OCT) apparatus includes an optical source, an interferometer generating an object beam and a reference beam, a transverse scanner for scanning an object with said object beam, and a processor for generating an OCT image from an OCT signal returned by said interferometer. At least the optical source, the interferometer, and the scanner are mounted on a common translation stage displaceable towards and away from said object. A dynamic focus solution is provided when the scanner and a folded object path are placed on the translation stage.

Abstract: A method for determining a characteristic of an analyte in a biological sample, the method comprising: directing broadband light by means of a sensing light path at the biological sample, at a target depth defined by the sensing light path and a reference light path; receiving the broadband light reflected from the biological sample by means of the sensing light path; directing the broadband light by means of the reference light path at a fixed reflecting device; and receiving the broadband light reflected from the fixed reflecting device by means of the reference light path.

Abstract: A method including: providing a low coherence scanning interferometry data for at least one spatial location of a sample having multiple interfaces, wherein the data is collected using a low coherence scanning interferometer having an illumination geometry and an illumination frequency spectrum, and wherein the data comprises a low coherence scanning interferometry signal having multiple regions of fringe contrast corresponding to the multiple interfaces; and determining a distance between at least one pair of interfaces based on a distance between the corresponding regions of fringe contrast and information about the illumination geometry.

Abstract: Disclosed is an interferometry analysis method that includes comparing information derivable from multiple interferometry signals corresponding to different surface locations of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parameterized by a series of characteristics that relate to one or more under-resolved lateral features of the test object; and outputting information about the under-resolved surface feature based on the comparison.

Abstract: An optical tomographic image obtaining apparatus, capable of obtaining optical tomographic images at high resolution, is miniaturized. During obtainment of an optical tomographic image, a mirror rotating section rotates a mirror, to rotate the irradiation direction of a measuring light beam. Operations of an optical path length changing section are controlled such that a measurement point along the optical path direction is moved for every rotation of the irradiation direction. A sheath rotating section rotates a sheath to move the position of a lens fixed within a lens holder by a threaded mechanism, to move the focusing position of the measuring light beam in the optical path direction, to match the position of the measurement point. Therefore, the movement speed of the focusing position can be reduced compared to conventional apparatuses. Accordingly, the necessity of a large focusing position moving means, which is capable of high speed movement, is obviated.

Abstract: Scanning interferometry data for a test object is provided, the data typically including intensity values for each of multiple scan positions for each of different spatial locations of the test object. The intensity values for each spatial location define an interference signal for the spatial location, and the intensity values for a common scan position define a data set for that scan position. Scan values are provided for each scan position, in which scan value increments between various scan values can be non-uniform. Information is determined about the test object based on the scanning interferometry data and scan values. The determination includes transforming at least some of the interference signals into a frequency domain with respect to the scan values.

Abstract: Methods and systems are disclosed for analyzing a scanning interferometry signal. A scanning interferometry signal is provided that is produced by a scanning interferometer for a first location of a test object (e.g., a sample having a thin film). A model function of the scanning interferometry signal is provided which is produced by the scanning interferometer. The model function is parametrized by one or more parameter values. The model function is fit to the scanning interferometry signal for each of a series of shifts in scan position between the model function and the scanning interferometry signal by varying the parameter values. Information is determined about the test object (e.g., a surface height or height profile, and/or a thickness or thickness profile for a thin film in the test object) at the first location based on the fitting.

Abstract: A surface profile measuring method using a broad bandwidth light source illuminating a sample surface and a reference surface through a splitter is provided. By changing a distance between the sample surface and the reference surface with a constant step, an interference diagram with a waveform composed of interference data points depicting a relationship of surface height versus illumination intensity is generated. In the beginning, a first data point with greatest illumination intensity is selected from the interference data points on the waveform. Then, a second data point is selected from the data points on the waveform within a predetermined range centered at the first data point to have the waveform showing best quality of symmetry. Then, a peak of a fringe defined by the second data point and its neighboring data points is estimated by using phase compensating approach.

Abstract: Methods, fourier domain optical coherence tomography (FDOCT) interferometers and computer program products are provided for removing undesired artifacts in FDOCT systems using continuous phase modulation. A variable phase delay is introduced between a reference arm and a sample arm of an FDOCT interferometer using continuous phase modulation. Two or more spectral interferograms having different phase delay integration times are generated. The spectral interferograms are combined using signal processing to remove the undesired artifacts. Systems and methods for switching between stepped and continuous phase shifting Fourier domain optical coherence tomography (FDOCT) and polarization-sensitive optical coherence tomography (PSOCT) are also provided herein.

Abstract: Two-dimensional and three-dimensional optical coherence tomography is obtained by differential imaging of full-frame interference images using a white light source. Full-color tomographic imaging is also possible by processing the three-color channels of the interference images. A technique is described to obtain two-dimensional OCT images with full natural color representation. In a particular embodiment, the interference image is acquired using a color camera and the three-color channels are processed separately, recomposing the final image. In an additional embodiment, the interference images are acquired using separate red, blue and green light sources and the three color channels are combined to recompose the final image.

Abstract: An optical image measuring apparatus capable of measuring an object to be measured which includes a birefringent layer in a short time is provided. The optical image measuring apparatus includes a broad-band light source, lenses for increasing a diameter of the light beam, a polarizing plate, a half mirror, a wavelength plate for converting the reference light to circularly polarized light, a wavelength plate for converting the signal light to circularly polarized light and converting the signal light to linearly polarized light, a frequency shifter, a polarization beam splitter for separating an S-polarized light component and a P-polarized light component from interference light, CCDs for receiving the respective polarized light components and outputting detection signals each including intensity change information, and a signal processing portion for forming an image reflecting a birefringent property, of an object to be measured based on the intensity change information.

Abstract: A system, apparatus and method for performing low coherence ranging of a sample with high transverse resolution and large depth of focus can be provided. For example, an optical ranging system including a light source can be used. Certain exemplary arrangement can be provided, e.g., a first arrangement for directing light from the light source to the sample, a second arrangement for directing reflected light from the sample to a detector, at least one detector, and a third arrangement for processing light data received by the detector and which generates an image can be utilized. Further, for example, an optical element can be provided which can have a transverse resolution defined as .?ris less than or equal to about ?5 m, and a depth of focus ?z of at least about 50 ?m.

Abstract: An integrated optical sensor, using low coherence interferometry, is capable of determining analyte concentration in a material sample based on absorption, scattering and polarization. The sensor includes one or more light collectors, with each collector having a separation distance from the region where the sample is illuminated by the source. The light backscattered from the sample is combined with reference arm light at the same optical path length for each light collector. The intensity of interference may be correlated with the concentration of an analyte in the material, for example the glucose concentration in a turbid medium like skin. The sensor operation can be based on fiber optics technology, integrated optics, or a combination of these. The operation is such that the spectrally resolved scattering and absorption coefficients can be measured simultaneously. In addition, the operation of the sensor can be synchronized with other sensors, for example temperature, pressure, or heartrate.

Abstract: Methods and related systems for determining properties of optical systems (e.g., interferometers) and/or optical elements (e.g., lenses and/or lens systems) are described. For example, information related to an optical thickness mismatch of an interferometer can be determined by providing scanning interferometry data. The data typically include obtaining one or more interference signals each corresponding to a different spatial location of a test object. A phase is determined for each of multiple frequencies of each interference signal. The information related to the optical thickness mismatch is determined based on the phase for each of the multiple frequencies of the interference signal(s).

Abstract: A method for determining a spatial property of an object includes obtaining a scanning low coherence interference signal from a measurement object that includes two or more interfaces. The scanning low coherence interference signal includes two or more overlapping low coherence interference signals, each of which results from a respective interface. Based on the low coherence interference signal, a spatial property of at least one of the interfaces is determined. In some cases, the determination is based on a subset of the low coherence interference signal rather than on the entirety of the signal. Alternatively, or in addition, the determination can be based on a template, which may be indicative of an instrument response of the interferometer used to obtain the low coherence interference signal.

Abstract: A method for determining a spatial property of an object includes obtaining a scanning low coherence interference signal from a measurement object that includes two or more interfaces. The scanning low coherence interference signal includes two or more overlapping low coherence interference signals, each of which results from a respective interface. Based on the low coherence interference signal, a spatial property of at least one of the interfaces is determined. In some cases, the determination is based on a subset of the low coherence interference signal rather than on the entirety of the signal. Alternatively, or in addition, the determination can be based on a template, which may be indicative of an instrument response of the interferometer used to obtain the low coherence interference signal.

Abstract: An optical system includes a photolithography system, a low coherence interferometer, and a detector. The photolithography system is configured to illuminate a portion of an object with a light pattern and has a reference surface. The low coherence interferometer has a reference optical path and a measurement optical path. Light that passes along the reference optical path reflects at least once from the reference surface and light that passes along the measurement optical path reflects at least once from the object. The detector is configured to detect a low coherence interference signal including light that has passed along the reference optical path and light that has passed along the measurement optical path. The low coherence interference signal is indicative of a spatial relationship between the reference surface and the object.

Abstract: A coherent radiation imaging system that produces digital images with a reduced amount of speckle. Radiation from a long coherence length source is used to form an image of a sample. The output coherent wave is temporally divided into a plurality of wavelets. The spatial phase of each wavelet is then modulated a known and different amount. Each phase modulated wavelet illuminates the sample and is perturbed by its interaction with the sample. A spatial phase map of each perturbed wavelet is then created and converted to a sample image with an image reconstruction program. The plurality of sample images thus formed is statistically averaged to form a final averaged image. The high frequency speckle that is not optically resolvable tends to average to zero with continual statistical averaging, leaving only the optically resolvable lower frequency phase information.

Abstract: In a compact optical device, a light emitting area of a light source and a light sensing area of a detector are placed in proximity. The detector receives part of a beam which is reflected back to the source from a sample. As a result, a beam splitter is no longer needed. By eliminating the beam splitter and packing the light source and detector in closeness, dimensions of the optical device are reduced.

Abstract: In accordance with the present invention, embodiments of interferometers are presented that improves both the polarization dependency problem and helps prevents light from being reflected back into the light source, among other things. Interferometer embodiments can include an isolator coupled to a light source and polarization dependent optics coupled with the isolator to provide light to a reference arm and a sample arm, wherein reflected light provided to optical detectors is such that a polarization independent optical signal can be formed in an optical signal processor coupled to the optical detectors, and the isolator blocks reflected light from the reference arm and the sample arm from entering the light source. In some embodiments, a balanced detection system can be utilized to reduce noise.

Abstract: A method includes providing scanning interferometry data for a test object, the data including intensity values for each of multiple scan positions for each of different spatial locations of the test object, the intensity values for each spatial location defining an interference signal for the spatial location, the intensity values for a common scan position defining a data set for that scan position. The method includes providing a scan value for each scan position, wherein increments between the scan values are non-uniform, transforming at least some of the interference signals into a frequency domain with respect to the scan values, and determining information about the test object based on the transformed interference signals.

Abstract: A method including comparing information derivable from a scanning interferometry signal for a first surface location of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parametrized by a series of characteristics for the test object. The information corresponding to the multiple models may include information about at least one amplitude component of a transform of a scanning interferometry signal corresponding to each of the models of the test object.

Abstract: A fiber characterization arrangement utilizes Fourier domain optical coherence tomography (FDOCT) to measure the cross-section of optical fibers, thus providing information sub-surface features, coating thickness/concentricity and stress-induced birefringence under tension. The FDOCT technique can also be used to study microstructured fibers. By making FDOCT measurements on a fiber placed in a cavity, the geometric and optical thickness of the fiber can be simultaneously measured, allowing for the determination of the refractive index of the fiber.

Abstract: An optical image measuring apparatus capable of effectively obtaining a direct current component of a heterodyne signal which is composed of background light of interference light is provided.

Abstract: Arrangements, apparatus and methods are provided according to exemplary embodiments of the present invention. In particular, at least one first electro-magnetic radiation may be received and at least one second electro-magnetic radiation within a solid angle may be forwarded to a sample. The second electro-magnetic radiation may be associated with the first electro-magnetic radiation. A plurality of third electro-magnetic radiations can be received from the sample which is associated with the second electro-magnetic radiation, and at least one portion of the third electro-magnetic radiation is provided outside a periphery of the solid angle. Signals associated with each of the third electro-magnetic radiations can be simultaneously detected, with the signals being associated with information for the sample at a plurality of depths thereof. The depths can be determined using at least one of the third electro-magnetic radiations without a need to utilize another one of the third electro-magnetic radiations.

Abstract: The invention is an apparatus and method for second harmonic optical coherence tomography of a sample comprising a laser coupled to an interferometer which has a reference arm and in a sample arm. A nonlinear crystal in the reference arm generates a second harmonic reference signal. The sample typically backscatters some second harmonic light into the sample arm. A broadband beam splitter optically coupled to the reference arm and sample arm combines the signals from the reference arm and sample arm into interference fringes and a dichroic beam splitter splits the interference fringes into a fundamental and second harmonic interference signal. A detector is optically coupled to the dichroic beam splitter detects interference fringes from which both an OCT and second harmonic OCT image can be constructed using a conventional data processor.

Abstract: Provided is an optical image measuring apparatus capable of easily changing a scanning interval of an object to be measured in a depth direction with high precision.

Abstract: To provide an optical image measuring apparatus capable of calculating an intensity of a direct current component composed of background light based on a result obtained by detection of interference light and obtaining a signal intensity of the interference light using the calculated intensity. The apparatus includes: an optical interference system to divide a light beam into signal light and reference light, and the signal light propagating through an object to be measured and the reference light are superimposed to produce interference light; beam splitters for dividing it into three interference light beams; shutters to perform sampling; photo detectors for detecting the sampled interference light beams and converting them into electrical signals; and a signal processing portion for calculating the signal intensity of the interference light and the spatial phase distribution thereof based on the electrical signals.

Abstract: A method for determining a characteristic of tissue in a biological sample comprising: directing light at the biological sample at a first depth and receiving that light reflected from the biological; directing the light at a reflecting device and receiving that light reflected from the reflecting device. The method also includes: interfering the light reflected from the biological sample and the light reflected from the reflecting device; detecting light resulting from the interfering; and determining a first phase associated with the light resulting from the interfering based on the first depth. The method further includes: varying an effective light path length to define a second depth; determining a second phase associated with the light resulting from the interfering based on the second depth; and determining the characteristic of the biological sample from the first phase and the second phase.

Abstract: A method including comparing information derivable from a scanning interferometry signal for a first surface location of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parametrized by a series of characteristics for the test object. The derivable information being compared may relate to a shape of the scanning interferometry signal for the first surface location of the test object.

Abstract: An optical system and optical apparatus prevent degradation of the S/N ratio due to switching between OCT and OCM observation modes and attain a high S/N ratio in both the observation modes. The optical system includes a light source 1 and a light-branching member 2 for branching light from the light source 1 into a reference light path and a signal light path. An objective 3 is placed in the signal light path. A light-scanning system 5 scans light in the signal light path with respect to a sample 4 placed in the signal light path. A beam diameter changing optical system 6 changes the beam diameter of light entering or exiting the light-scanning system 5. A light-combining member 7 combines together the reference light path and the signal light path. A light-detecting element 8 detects light combined by the light-combining member 7.