A processer of an optical module is configured to control a voltage signal having a frequency for causing a movable mirror to resonate, and perform an intensity acquisition process. The intensity acquisition process is a process of acquiring a measurement light intensity of the interference light of the measurement light M times at a first time interval based on the frequency in each of a plurality of cycles among P cycles continuous in the voltage signal, acquiring an addition value of a plurality of the measurement light intensities mutually corresponding for the same number of times, acquiring a laser light intensity of the interference light of the laser light N times at a second time interval based on the frequency in each of the plurality of cycles, and acquiring an addition value of a plurality of the laser light intensities mutually corresponding for the same number of times.

A processer of an optical module is configured to control a voltage signal having a frequency for causing a movable mirror to resonate, and perform an intensity acquisition process. The intensity acquisition process is a process of acquiring a measurement light intensity of the interference light of the measurement light M times at a first time interval based on the frequency in each of a plurality of cycles among P cycles continuous in the voltage signal, acquiring an addition value of a plurality of the measurement light intensities mutually corresponding for the same number of times, acquiring a laser light intensity of the interference light of the laser light N times at a second time interval based on the frequency in each of the plurality of cycles, and acquiring an addition value of a plurality of the laser light intensities mutually corresponding for the same number of times.

A method of forming a Chemically Vapour Deposited polymeric conformal coating on a surface of a part (23). The method comprises placing the part (23) and a deposition regulator (28) in a deposition chamber (22); dispersing a gas into the chamber (22) from which the polymeric coating is deposited on the surface. The deposition regulator (28) is configured to control a localised flow of the gas in the deposition chamber (22) to promote a more uniform layer thickness of the polymeric coating on the surface.

Systems and methods for improved interferometric imaging are presented. One embodiment is a partial field frequency-domain interferometric imaging system in which a light beam is scanned in two directions across a sample and the light scattered from the object is collected using a spatially resolved detector. The light beam could illuminate a spot, a line or a two-dimensional area on the sample. Additional embodiments with applicability to partial field as well as other types of interferometric systems are also presented.

A holographic interferometer, comprising: at least one imaging device capturing an interference pattern created by at least two light beams; and at least one aperture located in an optical path of at least one light beam of the at least two light beams; wherein the at least one aperture is located away from an axis of the at least one light beam, thus transmitting a subset of the at least one light beam collected at an angle range.

Various optical systems equipped with diode laser light sources are discussed in the present application. One example system includes a diode laser light source for providing a beam of radiation. The diode laser has a spectral output bandwidth when driven under equilibrium conditions. The system further includes a driver circuit to apply a pulse of drive current to the diode laser. The pulse causes a variation in the output wavelength of the diode laser during the pulse such that the spectral output bandwidth is at least two times larger the spectral output bandwidth under the equilibrium conditions.

The present invention provides a surface emitting laser the wavelength-tunable band of which is wide. The wavelength-tunable surface emitting laser includes a first reflector (101), an active layer (103) disposed on the first reflector (101), a beam portion (110) disposed over the active layer (103) with an air gap therebetween, and a second reflector (120) disposed on the beam portion (110). The second reflector (120) has a distributed Bragg reflector consisting of a stack of dielectric layers. The beam portion (110) has a distributed Bragg reflector consisting of a stack of conductive semiconductor layers.

A method for characterising high aspect ratio (HAR) structures etched in a substrate includes, for at least one structure, an interferometric measurement step, carried out with a low-coherence interferometer positioned on a top surface of the substrate, for measuring with a measurement beam, at least one depth data relating to a depth of the HAR structure, and a first adjusting step for adjusting a diameter, at the top surface, of the measurement beam according to at least one top critical dimension (top-CD) data relating to a width of the HAR structure.

A method and system implementing the method for characterising structures etched in a substrate, such as a wafer, includes at least one structure etched in the substrate, an imaging step including the following steps: capturing, with an imaging device positioned on the top surface of the substrate, at least one image of a top surface of the substrate, and measuring a first data relating to the structure from at least one captured image, at least one interferometric measurement step, carried out with a low-coherence interferometer positioned on the top surface, for measuring with a measurement beam positioned on the structure, at least one depth data relating to a depth of the structure; and a first adjusting step for adjusting the measurement beam according to the first data.

Systems and methods for improved interferometric imaging are presented. One embodiment is a partial field frequency-domain interferometric imaging system in which a light beam is scanned in two directions across a sample and the light scattered from the object is collected using a spatially resolved detector. The light beam could illuminate a spot, a line or a two-dimensional area on the sample. Additional embodiments with applicability to partial field as well as other types of interferometric systems are also presented.