A variable focal length (VFL) imaging system comprises a camera system, a first high speed variable focal length (VFL) lens, a second high speed variable focal length (VFL) lens, a first relay lens comprising a first relay focal length, a second relay lens comprising a second relay focal length, and a lens controller. The first relay lens and the second relay lens are spaced relative to one another along an optical axis of the VFL imaging system by a distance which is equal to a sum of the first relay focal length and the second relay focal length. The first high speed VFL lens and the second high speed VFL lens are spaced relative to one another along the optical axis on opposite sides of an intermediate plane which is located at a distance equal to the first relay focal length from the first relay lens. The lens controller is configured to provide synchronized periodic modulation of the optical power of the first high speed VFL lens and the optical power of the second high speed VFL lens.

The present invention provides a gas measuring method based on photothermal effect in hollow-core optical fiber comprising: filling a target gas into the core of a hollow-core optical fiber; coupling a probe light and a periodically modulated pump light into the hollow-core optical fiber; absorbing the pump light by the target gas resulting in the periodic modulation of the phase of the probe light; demodulating the phase modulation information of the probe light to obtain the concentration of the target gas, wherein the pump laser is wavelength and/or amplitude modulated. In the present invention, two lasers including a pump laser and a probe laser are used for the measurement, this approach is simple and practical. Also, the use of the hollow-core optical fiber with extremely-small core area greatly increases the optical power density, thus enhances the strength of the detected photothermal signal; this method allows ppb level gas measurement with high selectivity, and is universally suitable for the detection of gases with absorption in near-infrared.

The present invention provides a gas measuring method based on photothermal effect in hollow-core optical fiber comprising: filling a target gas into the core of a hollow-core optical fiber; coupling a probe light and a periodically modulated pump light into the hollow-core optical fiber; absorbing the pump light by the target gas resulting in the periodic modulation of the phase of the probe light; demodulating the phase modulation information of the probe light to obtain the concentration of the target gas, wherein the pump laser is wavelength and/or amplitude modulated. In the present invention, two lasers including a pump laser and a probe laser are used for the measurement, this approach is simple and practical. Also, the use of the hollow-core optical fiber with extremely-small core area greatly increases the optical power density, thus enhances the strength of the detected photothermal signal; this method allows ppb level gas measurement with high selectivity, and is universally suitable for the detection of gases with absorption in near-infrared.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and a signal generator that outputs the reference signal input to the demodulation circuit and outputs a drive signal input to the optical modulator, in which Vd/Vr<10, where Vr is a voltage of the reference signal and Vd is a voltage of the drive signal.

A laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and a signal generator that outputs the reference signal input to the demodulation circuit and outputs a drive signal input to the optical modulator, in which Vd/Vr<10, where Vr is a voltage of the reference signal and Vd is a voltage of the drive signal.

Provided are an acousto-optic element, an acousto-optic element array, and a display apparatus including the acousto-optic element array. The acousto-optic element includes: an acousto-optic modulator which includes an acousto-optic layer formed of an acousto-optic material; a light supplier which supplies light to the acousto-optic modulator in a first direction; a first sound-wave modulator which applies first elastic waves to the acousto-optic modulator in a second direction; and a second sound-wave modulator which applies second elastic waves to the acousto-optic modulator in a third direction. The light supplied from the light supplier to the acousto-optic modulator is deflected by diffraction caused by the first elastic waves applied from the first sound-wave modulator and diffraction caused by the second elastic waves applied from the second sound-wave modulator, and is output from the acousto-optic modulator through a front side of the acousto-optic modulator.

A microscopy system that includes a first laser emitting a first laser pulse along a first beam line, the first laser pulse being converted into an annular Bessel pump beam; and a second laser emitting a second laser pulse along a second beam line, the second laser pulse being a probe beam, the annular Bessel pump beam and the probe beam being delivered to a sample at right angles to each other allowing the annular Bessel pump beam to shrink a focal axial diameter of the second beam line thereby enabling dipole-like backscatter stimulated emission along the second beam line.

A microscopy system that includes a first laser emitting a first laser pulse along a first beam line, the first laser pulse being converted into an annular Bessel pump beam; and a second laser emitting a second laser pulse along a second beam line, the second laser pulse being a probe beam, the annular Bessel pump beam and the probe beam being delivered to a sample at right angles to each other allowing the annular Bessel pump beam to shrink a focal axial diameter of the second beam line thereby enabling dipole-like backscatter stimulated emission along the second beam line.

The present invention concerns a method for generating a pattern of light, this method comprising the following steps: a) emitting an input laser pulse (P1), b) deflecting the input laser pulse (P1) by a first deflector (22) to obtain a first laser pulse, c) deflecting the first laser pulse (P3) by a second deflector (24) to obtain a second laser pulse (P4), and d) focusing the pulse (P4) by an optical element characterized in that: —the first deflector (22) shapes the first laser pulse (P3) according to a first function, —the second deflector (24) shapes the second laser pulse (P4) according to a second function, and —the first function f(x) and the second function g(y) are computed and/or optimized to obtain the desired pattern of light.

Method for determining the characteristics of a system for generating at least one pattern of light, the method comprising: a) providing a desired pattern of light, b) expressing the amplitude and the phase of the output pulse of the system as a function of the input laser pulse and in function of the characteristics of the system to obtain a calculated output pulse, the input laser pulse having a duration below or equal to 1 nanosecond, c) determining at least one characteristic of the system by minimizing a distance between the calculated output pulse and the desired output laser pulse.