Abstract: There is disclosed an optical measurement device which is based on optical interference and it uses a light beam which is radiated to and transmitted through or reflected by a sample, especially a light scattering medium to optically measure the sample. The amount of signal lights effective for optical heterodyne detection is increased, while speckle noises are averaged out. On an observation plane of a concerned point arranged are plural detector elements. From signals obtained by the respective detector elements, an optical signal of the concerned point is obtained.

Abstract: A laser device has a laser medium responsive to an excitation light for generating a laser beam consisting of a plurality of longitudinal modes when excited by an energy of the excitation light, two mirrors constituting a laser resonator for forming an optical path of the laser beam passing through said laser medium, and a nonlinear optical element, arranged in the laser resonator, for generating a second harmonic caused by one of the plurality of longitudinal modes constituting the laser beam generated in said laser medium and a sum-frequency caused by two of the plurality of longitudinal modes constituting the laser beam generated in said laser medium.

Abstract: An image measuring apparatus for measuring an image of a tooth or gum applies the radiation of a laser beam to permit extremely quick, reliable, safe detection of dental caries and other dental pathological conditions. The low incident power of the laser radiation would not cause damage or pain to the tissue, such as the tooth or gum. The image measuring apparatus is equipped with a light source which emits light having at least a wavelength in a range of 500 nm or more to less than 600 nm; it uses the light emitted from the light source to obtain 2-dimensional images or computed tomographic images of a tooth or gum from the light, which has been transmitted through the tooth or gum, by using an optical heterodyne detection method.

Abstract: An optical tomographic imaging equipment including a light-receiving unit having a plurality of light-receiving elements, and an electronic focusing control unit. The electronic focusing control unit provides a control such that a plurality of light-receiving signals, derived by light-receiving an interference wave involved in superposition of the reflected light and the reference light using the plurality of light-receiving elements of the light-receiving unit, are relatively delayed and added to each other so as to issue resultant light-receiving signals involved in emphasis of information of a predetermined point on a light path of the object light within the subject.