An atomic beam is irradiated with a first, a second, 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.

An optical coherence tomography apparatus includes a control unit configured, before a tomographic image to be stored is obtained using the output from the light receiving unit during a period in which the measurement light is scanned in a first scanning pattern for scanning an image capturing region of the subject eye, to control the optical scanning unit so as to repeatedly scan the measurement light in a second scanning pattern for scanning the measurement light over at least part of the image capturing region in a scanning time shorter than a scanning time of the first scanning pattern and to control the driving unit so as to drive the focusing unit using the output from the light receiving unit during a period in which the measurement light is repeatedly scanned in the second scanning pattern.

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.

A method and apparatus for quantitatively characterizing performance of a laser steering galvanometer mirror directs a laser beam from a calibration “sensor” onto a side region of the mirror to directly determine rotational positioning, velocity, and/or acceleration thereof using interferometry, time-of-flight measurements, and Doppler measurements. Measured positioning errors can be compared with a database to predict required calibration adjustments. Embodiments automatically adjust digital calibrations. Mirrors, splitters, and/or a plurality of sensors can apply measurement beams simultaneously or sequentially to both sides of a mirror, and/or to more than one mirror. Large rotation ranges, for example larger than +/−15 degrees, can be accommodated by applying measurement beams from a plurality of directions. The calibration apparatus can be distinct, or integral with the galvanometer, and can be used to monitor and/or to control the mirror positioning.

A method and apparatus for quantitatively characterizing performance of a laser steering galvanometer mirror directs a laser beam from a calibration “sensor” onto a side region of the mirror to directly determine rotational positioning, velocity, and/or acceleration thereof using interferometry, time-of-flight measurements, and Doppler measurements. Measured positioning errors can be compared with a database to predict required calibration adjustments. Embodiments automatically adjust digital calibrations. Mirrors, splitters, and/or a plurality of sensors can apply measurement beams simultaneously or sequentially to both sides of a mirror, and/or to more than one mirror. Large rotation ranges, for example larger than +/−15 degrees, can be accommodated by applying measurement beams from a plurality of directions. The calibration apparatus can be distinct, or integral with the galvanometer, and can be used to monitor and/or to control the mirror positioning.

An acousto-optic modulator (AOM) laser frequency shifter system includes a laser configured to generate an incident beam, a first optical splitter optically coupled to the laser and configured to split the incident beam into at least one portion of the incident beam, at least one phase-shift channel optically coupled to the first optical splitter and configured to generate at least one frequency-shifted beam with an acousto-optic modulator (AOM) from the at least one portion of the incident beam received from the first optical splitter, and a second optical splitter configured to receive the at least one frequency-shifted beam from the at least one phase-shift channel and configured to direct the at least one frequency-shifted beam to an interferometer configured to acquire an interferogram of a sample with the at least one frequency-shifted beam.

A motion detector adapted to detect activity of extremely small scale organisms, such as micro-organisms, bacteria and fungi, and even of viruses and genetic material, such as DNA and RNA. The motion detector is capable of detecting nano-motion, that is, motion in the order of nanometers or less.

A position measurement system including a first interferometer and a second interferometer arranged to determine a distance of the object in a first direction when the object is in a first measurement area by emitting beams onto a target surface of the object. The position measurement system further has a third interferometer and a fourth interferometer arranged to determine a distance of the object in the first direction when the object is in a second measurement area by emitting beams onto the target surface of the object. An arrangement of relative positions in a second direction of beams spots impinging on the target surface from the beams emitted by the first and second interferometers is different from an arrangement of relative positions in the second direction of beams spots impinging on the target surface from the beams emitted by the third and fourth interferometers.

A position measurement system including a first interferometer and a second interferometer arranged to determine a distance of the object in a first direction when the object is in a first measurement area by emitting beams onto a target surface of the object. The position measurement system further has a third interferometer and a fourth interferometer arranged to determine a distance of the object in the first direction when the object is in a second measurement area by emitting beams onto the target surface of the object. An arrangement of relative positions in a second direction of beams spots impinging on the target surface from the beams emitted by the first and second interferometers is different from an arrangement of relative positions in the second direction of beams spots impinging on the target surface from the beams emitted by the third and fourth interferometers.

A heterogeneous integration detecting method and a heterogeneous integration detecting apparatus are provided. The heterogeneous integration detecting method includes the following. Under the condition of maintaining the same relative distance between an interference objective lens and a sample, the relative posture of the interference objective lens and the sample is continuously adjusted according to the change of an image of the sample in the field of view of the interference objective lens until a first optical axis of the interference objective lens is determined to be substantially perpendicular to the surface of the sample according to the image. The interference objective lens is replaced with an imaging objective lens and the geometric profile of at least one via of the sample is detected. A second optical axis of the imaging objective lens after replacement overlaps with the first optical axis of the interference objective lens before replacement.