Methods and apparatus are provided for imaging a response of a sample to radiative heating. A method in accordance with one embodiment has steps of: illuminating a first area of the sample with a radiative heating beam; illuminating a portion of the first area with a probe beam; collecting light exiting the sample due to interaction of the probe beam with the sample; superimposing the light exiting the sample with a reference beam derived from the probe beam, wherein the reference is characterized by an optical phase relative to the probe beam; detecting a spatial portion of the light exiting the sample and the reference beam with at least one detector to generate an interference signal; and processing the interference signal to obtain an image of the sample associated with absorption of the radiative heating beam.

Retinal imaging systems and related methods employ a user specific approach for controlling the reference arm length in an optical coherence tomography (OCT) imaging device. A method includes restraining a user's head relative to an OCT imaging device. A reference arm length adjustment module is controlled to vary a reference arm length to search a user specific range of reference arm lengths to identify a reference arm length for which the OCT image detector produces an OCT signal corresponding to the retina of the user. The user specific range of reference arm lengths covers a smaller range of reference arm lengths than a reference arm length adjustment range of the reference arm length adjustment module.

An atomic beam is irradiated with a first laser beam, a second laser beam, and a third laser beam. The first laser beam and the third laser beam each have a wavelength corresponding to a transition between a ground state and a first excited state. The second laser beam has a wavelength corresponding to a transition between the ground state and a second excited state. First, atoms each having a smaller velocity component than a predetermined velocity in a direction orthogonal to the traveling direction of the atomic beam are changed from the ground state to the first excited state by the first laser beam. Subsequently, a momentum is provided for individual atoms in the ground state by the second laser beam, which removes the atoms from the atomic beam. Finally, atoms in the first excited state are returned from the first excited state to the ground state by the third laser beam.

The present invention provides a surface shape measuring device and a surface shape measuring method which do not require a physical reference plane and can improve measurement accuracy without using a mechanical adjustment mechanism. The illumination light condensing point P.sub.Q and the reference light condensing point P.sub.L are arranged as mirror images of each other with respect to the virtual plane VP, and each data of the object light O, being a reflected light of the spherical wave illumination light Q, and the inline spherical wave reference light L is recorded on each hologram. On the virtual plane VP, the reconstructed object light hologram h.sup.V for measurement is generated, and the spherical wave optical hologram s.sup.V representing a spherical wave light emitted from the reference light condensing point P.sub.L is analytically generated. The height distribution of the surface to be measured of the object 4 is obtained from the phase distribution obtained by dividing the reconstructed object light hologram h.sup.V by the spherical wave light hologram s.sup.V. High-accuracy surface shape measurement without requiring a reference plane such as a glass substrate is realized by comparing the phase data of the reflected light acquired from the surface to be measured and the phase distribution on the plane cut surface of the spherical wave obtained analytically.

Systems and methods for alignment and testing of a photonic device include a light source, an interferometer, a detector, and a processing circuit. The processing circuit may generate control signal(s) for the light source to project a beam through the interferometer to a device under testing (DUT). The interferometer may receive an interference beam from an optical fiber of the DUT. The processing circuit may align optical fiber(s) for the DUT, determine one or more characteristics for the DUT, and so forth based on the interference beam and a reference beam generated by the interferometer.

Provided herein are devices and systems comprising a light source which provides a beam to an optical module via a multimode fiber, an interference objective module outputs the beam processed by the optical module and collects interference signals from a sample; and a detector which detects the interference signals from the interference objective module wherein the optical module comprises an etendue squeezing component configured to slice the beams to at least two sub-beams and homogenize the sub-beams to an illumination field and match the shapes of the illumination field with the region of interest.

A light source projects a light beam. An interferometer includes a splitting unit that splits the light beam. The interferometer generates interference beams with the respective split light beams. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam and a reference beam passing through an optical path. A light-receiving unit receives the interference beams. A processor calculates a distance to the measurement target by associating at least one detected peak with at least one of the spots in accordance with a mirror surface mode or a rough surface mode. The optical path length difference is made different among the split light beams. In the mirror surface mode, the processor uses a distance calculated based on a peak corresponding to a spot for which the optical path length difference is shortest.

A light source projects a light beam. An interferometer includes a splitting unit that splits the light beam. The interferometer generates interference beams with the respective split light beams. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam and a reference beam passing through an optical path. A light-receiving unit receives the interference beams. A processor calculates a distance to the measurement target by associating at least one detected peak with at least one of the spots in accordance with a mirror surface mode or a rough surface mode. The optical path length difference is made different among the split light beams. In the mirror surface mode, the processor uses a distance calculated based on a peak corresponding to a spot for which the optical path length difference is shortest.

A laser interferometer includes: a laser light source; a collimator configured to generate collimated light; an optical modulator configured to modulate the collimated light into reference light having a different frequency; and a light receiving element configured to receive object light and the reference light and output a light receiving signal, in which when an optical axis of the collimated light is a first optical axis, when return light is generated, an optical axis of the return light is a second optical axis, a position at which the collimated light is generated is a reference position, the following equation (A) is satisfied:

[00001]$\begin{array}{cc}\frac{K}{2}+\frac{1}{2}\left(R+\frac{2L}{R}\lambda \right)\leqq \Delta y& \left(A\right)\end{array}$

in which Δy is a shift width between the first optical axis and the second optical axis at the reference position, κ is an effective diameter of the collimator, R is a light diameter of the collimated light, L is a distance between the reference position and the optical modulator, and Λ is a wavelength of the collimated light.

A laser interferometer includes: a laser light source; a collimator configured to generate collimated light; an optical modulator configured to modulate the collimated light into reference light having a different frequency; and a light receiving element configured to receive object light and the reference light and output a light receiving signal, in which when an optical axis of the collimated light is a first optical axis, when return light is generated, an optical axis of the return light is a second optical axis, a position at which the collimated light is generated is a reference position, the following equation (A) is satisfied:

[00001]$\begin{array}{cc}\frac{K}{2}+\frac{1}{2}\left(R+\frac{2L}{R}\lambda \right)\leqq \Delta y& \left(A\right)\end{array}$

in which Δy is a shift width between the first optical axis and the second optical axis at the reference position, κ is an effective diameter of the collimator, R is a light diameter of the collimated light, L is a distance between the reference position and the optical modulator, and Λ is a wavelength of the collimated light.