Abstract:
An adaptive optics system includes a spatial light modulator configured to spatially modulate a phase of an optical image incident on a modulation surface including N two-dimensionally arranged regions and a wavefront sensor including a lens array having N two-dimensionally arranged lenses corresponding to the N regions and an optical detection element for detecting a light intensity distribution including M converging spots formed by the lens array and configured to receive the optical image after the modulation from the spatial light modulator, and compensates for the wavefront distortion by controlling a phase pattern displayed in the spatial light modulator based on a wavefront shape of the optical image obtained from the light intensity distribution, wherein a correspondence relation between the region of the spatial light modulator and the converging spot formed in the wavefront sensor is specified while the compensation for the wavefront distortion is executed.
Abstract:
In an aberration-correcting method according to an embodiment of the present invention, in an aberration-correcting method for a laser irradiation device 1 which focuses a laser beam on the inside of a transparent medium 60, aberration of a laser beam is corrected so that a focal point of the laser beam is positioned within a range of aberration occurring inside the medium. This aberration range is not less than n×d and not more than n×d+Δs from an incidence plane of the medium 60, provided that the refractive index of the medium 60 is defined as n, a depth from an incidence plane of the medium 60 to the focus of the lens 50 is defined as d, and aberration caused by the medium 60 is defined as Δs.
Abstract:
A dispersion measuring device includes a pulse forming unit, a light detection unit, a control unit, and an arithmetic operation unit. The control unit selectively outputs a first phase pattern and a second phase pattern. The pulse forming unit forms an optical pulse train from initial pulsed light, the optical pulse train including a plurality of optical pulses having a time difference from each other and having different center wavelengths from each other. The light detection unit detects a temporal waveform of the optical pulse train. The arithmetic operation unit estimates a wavelength dispersion amount of a measurement object based on a feature amount of the temporal waveform of the optical pulse train. When the first phase pattern is output, a pulse having a long center wavelength is generated first. When the second phase pattern is output, a pulse having a short center wavelength is generated first.
Abstract:
A dispersion measurement apparatus includes a pulse forming unit, a correlation optical system, a photodetection unit, and an operation unit. The pulse forming unit forms a light pulse train including a plurality of light pulses having time differences and center wavelengths different from each other from a measurement target light pulse output from a pulsed laser light source. The correlation optical system receives the light pulse train output from the pulse forming unit and outputs correlation light including a cross-correlation or an autocorrelation of the light pulse train. The photodetection unit detects a temporal waveform of the correlation light output from the correlation optical system. The operation unit estimates a wavelength dispersion amount of the pulsed laser light source based on a feature value of the temporal waveform of the correlation light.
Abstract:
A dispersion measurement apparatus includes a pulse forming unit, an imaging unit, and an operation unit. The pulse forming unit forms a light pulse train including a plurality of light pulses having time differences and center wavelengths different from each other from a light pulse output from a pulsed laser light source. The imaging unit includes an image sensor capable of performing imaging at an imaging interval shorter than a minimum peak interval of the light pulse train, and images a light pulse train passed through a measurement object to generate imaging data. The operation unit receives the imaging data, detects a temporal waveform of the light pulse train for each pixel of the image sensor, and estimates a wavelength dispersion amount of the measurement object for each pixel of the image sensor based on a feature value of the temporal waveform.
Abstract:
A time response measurement apparatus includes a pulse formation unit, an attenuation unit, a waveform measurement unit, and an analysis unit. The pulse formation unit generates first pulsed light including a wavelength of pump light, second pulsed light including a wavelength of probe light, and third pulsed light including the wavelength of the pump light and the wavelength of the probe light, on a common optical axis. The attenuation unit transmits the first pulsed light, the second pulsed light, and the third pulsed light output from a sample arranged on the optical axis after being incident on the sample. An attenuation rate for the pump light is larger than an attenuation rate for the probe light. The analysis unit obtains a time response of the sample based on temporal waveforms of the first pulsed light, the second pulsed light, and the third pulsed light having passed through the attenuation unit.
Abstract:
An optical measurement device includes a light pulse source, a light separator unit, a wave synthesizer unit, an optical detection unit, and a measurement unit. The light pulse source outputs a plurality of light pulses having different temporal waveforms and different center wavelengths. The light separator unit spatially separates the light pulses and causes the light pulses to be incident on a measurement object. The wave synthesizer unit synthesizes the light pulses reflected by the measurement object or transmitted through the measurement object and emits the synthesized light pulses onto one optical path. The optical detection unit receives the light pulses emitted from the wave synthesizer unit and outputs a temporal waveform signal of the light pulses. The measurement unit measures timings when the light pulses each are received by the optical detection unit or a difference between the timings on a basis of the temporal waveform signal.
Abstract:
A dispersion measurement apparatus includes a pulse forming unit, a correlation optical system, a photodetection unit, and an operation unit. The pulse forming unit forms a light pulse train including a plurality of light pulses having time differences and center wavelengths different from each other from a measurement target light pulse output from a pulsed laser light source. The correlation optical system receives the light pulse train output from the pulse forming unit and outputs correlation light including a cross-correlation or an autocorrelation of the light pulse train. The photodetection unit detects a temporal waveform of the correlation light output from the correlation optical system. The operation unit estimates a wavelength dispersion amount of the pulsed laser light source based on a feature value of the temporal waveform of the correlation light.
Abstract:
A data generating device sets an initial candidate solution of an intensity spectrum function, a phase spectrum function, and an initial temperature and a cooling rate, generates a neighborhood solution, transforms a first waveform function of a frequency domain including the neighborhood solution and the phase spectrum function into a second waveform function of a time domain including a time-intensity waveform function and a time-phase waveform function and calculates an evaluation value representing a degree of difference between the time-intensity waveform function and the desired time-intensity waveform, sets the neighborhood solution as an n-th candidate solution for a certain probability, and lowers the temperature on the basis of the cooling rate. A decrease in the temperature acts in a direction in which the probability P is lowered when the evaluation value of the neighborhood solution is worse than the evaluation value of the candidate solution.
Abstract:
A modulation pattern calculation apparatus includes an iterative Fourier transform unit, a filtering process unit, and a modulation pattern calculation unit. The iterative Fourier transform unit performs a Fourier transform on a waveform function including an intensity spectrum function and a phase spectrum function, performs a replacement of a temporal intensity waveform function based on a desired waveform after the Fourier transform and then performs an inverse Fourier transform, and performs a replacement to constrain the phase spectrum function after the inverse Fourier transform. The filtering process unit performs a filtering process of cutting a part exceeding a cutoff intensity for each wavelength, on the intensity spectrum function in a frequency domain.