Abstract: A vibrational circular dichroism (VCD) spectroscopy method and apparatus that can significantly reduce the measurement time needed to acquire a differential absorption spectrum compared to known approaches. A dual-comb is generated by superimposing the outputs from two quantum cascade laser sources, thus providing a third comb interferogram with beat frequencies higher than the polarization modulation frequency. Consequently, for each of the left and right circularly polarized light, the measurement signal measures transmission through the sample across the full wavelength range of interest during each period of the polarization modulation. A complete vibrational spectrum is thus acquired in each modulation of a polarization modulator, instead of only acquiring data for a single wavelength during each modulation of the polarization, as in dispersive or tunable laser VCD, or only a single Fourier component of the spectrum, as in Fourier transform VCD.

Abstract: A dual-comb spectrometer 5 with two lasers 10, 12 serving as a local oscillator and an interrogator. The lasers output light beams with respective frequency combs C1, C2 of defined free spectral range, FSR. A detector 30 can detect heterodyne mixing of the combined beams to detect an RF frequency comb C3. Respective control signals are supplied to the lasers which have functional forms configured to cause the frequencies of the lasers' frequency combs C1, C2 to tune over a defined fraction of their FSR. This enables a reduction of the effective spectral sampling period by a factor equal to the ratio of the FSR to the spectral resolution of the spectrometer, which will typically be several orders of magnitude, so that the spectral sampling period can be reduced from the GHz to the MHz range, which in turn enables a gapless spectrum to be obtained in a short time.

Abstract: A vibrational circular dichroism (VCD) spectroscopy method and apparatus that can significantly reduce the measurement time needed to acquire a differential absorption spectrum compared to known approaches. A dual-comb is generated by superimposing the outputs from two quantum cascade laser sources, thus providing a third comb interferogram with beat frequencies higher than the polarization modulation frequency. Consequently, for each of the left and right circularly polarized light, the measurement signal measures transmission through the sample across the full wavelength range of interest during each period of the polarization modulation. A complete vibrational spectrum is thus acquired in each modulation of a polarization modulator, instead of only acquiring data for a single wavelength during each modulation of the polarization, as in dispersive or tunable laser VCD, or only a single Fourier component of the spectrum, as in Fourier transform VCD.

Abstract: A dual-comb spectrometer 5 with two lasers 10, 12 serving as a local oscillator and an interrogator. The lasers output light beams with respective frequency combs C1, C2 of defined free spectral range, FSR. A detector 30 can detect heterodyne mixing of the combined beams to detect an RF frequency comb C3. Respective control signals are supplied to the lasers which have functional forms configured to cause the frequencies of the lasers' frequency combs C1, C2 to tune over a defined fraction of their FSR. This enables a reduction of the effective spectral sampling period by a factor equal to the ratio of the FSR to the spectral resolution of the spectrometer, which will typically be several orders of magnitude, so that the spectral sampling period can be reduced from the GHz to the MHz range, which in turn enables a gapless spectrum to be obtained in a short time.

Abstract: An optical frequency comb setup including a semiconductor cascade laser drivable by a laser driver, emitting a laser beam through an end facet of the semiconductor cascade laser with a frequency comb with at least two given individual emission frequencies, repetition frequency, carrier envelope offset frequency shows improved comb stability and/or comb formation and/or comb bandwidth. This is achieved by an external cavity added outside of the cavity of the semiconductor cascade laser, having a reflective element with a mirror surface reflecting the at least two individual emission frequencies being arranged in a relative distance to the end facet allowing to adapt repetition frequency and/or carrier envelope offset frequency and/or the dispersion seen by the light in the optical frequency comb setup.

Abstract: A Multi-pass optical cell (1) with an internal space (11) for laser spectroscopy is described, which is able to reduce or eliminate interference fringes appearing by performing laser absorption spectroscopy in the multi-pass optical cells (1) leading to improved absorption spectra. This is achieved by using a multi-pass optical cell (1) comprising an absorption mask (3) which is permanently or removable mountable in the internal space (11) in a rotatably fixed manner, where in a mask wall (30) a plurality of m apertures (300) is formed, in which the position of each aperture (300) is adapted to a predefinable propagation path of a main optical beam and/or the resulting reflection spot pattern (211) defined by the geometry of the multi-pass optical cell (1) and the used angle of incidence of an initial beam (20), so that each aperture (300) is traversable by the main optical beam from a first side (301) to a second side (302).

Abstract: A Multi-pass optical cell (1) with an internal space (11) for laser spectroscopy is described, which is able to reduce or eliminate interference fringes appearing by performing laser absorption spectroscopy in the multi-pass optical cells (1) leading to improved absorption spectra. This is achieved by using a multi-pass optical cell (1) comprising an absorption mask (3) which is permanently or removable mountable in the internal space (11) in a rotatably fixed manner, where in a mask wall (30) a plurality of m apertures (300) is formed, in which the position of each aperture (300) is adapted to a predefinable propagation path of a main optical beam and/or the resulting reflection spot pattern (211) defined by the geometry of the multi-pass optical cell (1) and the used angle of incidence of an initial beam (20), so that each aperture (300) is traversable by the main optical beam from a first side (301) to a second side (302).

Abstract: An actuator load beam comprising a preload bend section defining an array of differently configured stiffness-reducing features. The stiffness-reducing features are characteristically sized in inverse relation to a respective distance from a longitudinal centerline of the actuator load beam at the preload bend section. An associated method comprising determining a thickness of a preload bend section for an actuator load beam associated with a desired resonant performance; determining a volume of stiffness-reducing features in the preload bend section associated with a desired vertical stiffness; and arranging an array of stiffness-reducing features associated with the determined volume in an array of sequentially smaller size with the largest size of the array being disposed nearest to a longitudinal centerline of the actuator load beam at the preload bend section.

Abstract: A monocoque head suspension carries a read-write head on a distal end and is attachable at a proximal end to an actuator assembly. The monocoque head suspension includes a bottom skin and a top skin, and also a core positioned between the bottom and top skins. The core has voids therein that form hollow regions between the bottom and top skins. The core may be made of low-density material, such as photo-imageable epoxy, polyamide or polyimide, deposited on the bottom skin, or may be a separately formed piece. The bottom skin and top skin may be made of a stainless steel material. The monocoque head suspension may be a component of an assembly to store data to a magnetic medium and read data from the medium.

Abstract: A monocoque head suspension carries a read-write head on a distal end and is attachable at a proximal end to an actuator assembly. The monocoque head suspension includes a bottom skin and a top skin, and also a core positioned between the bottom and top skins. The core has voids therein that form hollow regions between the bottom and top skins. The core may be made of low-density material, such as photo-imageable epoxy or polyimide, deposited on the bottom skin, or may be a separately formed piece. The bottom skin and top skin may be made of a stainless steel material. The monocoque head suspension may be a component of an assembly to store data to a magnetic medium and read data from the medium.