Methods and systems for forming holographic gratings are described herein. The methods and systems may decrease the amount of haze produced during exposure of a holographic recording medium. In some embodiments, the methods and systems include a holographic recording medium; a master hologram containing a grating; and a light source and moveable deflector configured to diffract light through the master hologram into the holographic medium to form a holographic interference pattern. The moveable deflector is configured to move in a direction parallel to the extending direction of the grating. Advantageously, moving the light in this direction allows the holographic interference pattern to remain stationary while there is a spatio-temporal displacement and cancellation of unwanted intensity nonuniformities.

An calibration kit includes a base, a combination of calibration parts, and a manipulation part. The combination of calibration parts is disposed on the base and includes a first calibration part and a second calibration part. The first calibration part has a first calibration surface. The second calibration part has a second calibration surface. The first calibration part and the second calibration part are relatively movable in a movement direction and are movable relative to the base. The manipulation part is movably or rotatably disposed on the base. The manipulation part is configured to be operable to drive the first calibration part and the second calibration part to move in the movement direction relative to the base, so that the combination of calibration parts forms a three-dimensional calibration surface configuration through the first calibration surface and the second calibration surface.

A two-photon-polymerization laser direct writing system based on an acousto-optic deflector is provided, which includes an ultrafast laser device, a beam expander, a scanning field center angular dispersion compensator, a two-dimensional acousto-optic deflector, a scanning field edge angular dispersion compensator, an astigmatism compensator and a focusing objective lens, the ultrafast laser device is configured to emit an ultrafast laser; the scanning field center angular dispersion compensator is configured to conduct precompensation on an angular dispersion at a center of a scanning field; the two-dimensional acousto-optic deflector is configured to deflect the ultrafast laser on the angular dispersion at the center of the scanning field; the scanning field edge angular dispersion compensator is configured to compensate for an angular dispersion at an edge of the scanning field; the astigmatism compensator is configured to compensate for astigmatism; the focusing objective lens is configured to conduct tight-focusing on the ultrafast laser.

A mirror unit includes an optical scanning device, a frame member, and a window member. The frame member includes first and second wall portions facing each other in an X-axis direction. The first wall portion is higher than the second wall portion. The window member is disposed on a top surface of the first wall portion and a top surface of the second wall portion and is inclined with respect to a mirror surface of the optical scanning device. In a cross-section parallel to the X-axis direction, the first wall portion is separated from a first line passing through a first end at a side of the first wall portion in the mirror surface and a first corner portion formed at the side of the first wall portion by an outer surface opposite to the frame member and a first side surface in the window member.

First and second types of object detectors, a sensing device, and a mobile apparatus. The first and second types of object detectors include a light source configured to emit light, photoreceptor configured to receive the light reflected by an object, and a binarizing circuit configured to binarize a signal sent from the photoreceptor at a threshold V.sub.th. In the first and second types of object detectors, object detection processes are performed in a same direction until a high-level signal is output M times from the signal binarized by the binarizing circuit. In the first type of object detector, a value of the M is determined based on an incidence of shot noise where peak intensity exceeds the threshold V.sub.th in the photoreceptor. In the second type of object detector, a threshold V.sub.th is set based on a value of the M.

An apparatus including: a deflector deflecting a light flux from a light source to scan a surface in a main scanning direction; and an imaging optical system including first and second optical elements, and guiding the light flux deflected by the deflector to the surface. When sagittal shapes of an incident surface and an exit surface of each of the first and second optical elements are represented by the following equations:

[00001]$x=\frac{z^2/r^{\prime }}{1+{\left(1-{\left(z/r^{\prime }\right)}^2\right)}^{1/2}}+\underset{n=1}{\overset{8}{.Math.}}\underset{m=0}{\overset{16}{.Math.}}{M}_{\mathrm{mn}}{y}^m{z}^n$$r^{\prime }=r\left(1+\underset{i=1}{\overset{16}{.Math.}}{E}_i{y}^i\right)$

in at least one of incident surface or exit surface of first optical element and each of incident surface and exit surface of second optical element, at least one of values of M.sub.m n is not equal to 0 provided that m is not equal to 0, and incident surface and exit surface of second optical element have M.sub.01 of the same sign.

A vehicle lamp includes a light source, and an aberration correction lens unit, that corrects chromatic aberration, irradiates in a frontward direction with direct light from the light source. The aberration correction lens unit includes a first lens located in a front side of the light source, and a second lens located in front of the first lens. The aberration correction lens unit performs vibration control for vibrating intersections in a front-back direction. The intersections are intersections of an optical axis, and red, green, and blue components of white light incident in parallel from the front toward the outside in the radial direction from the optical axis side of the aberration correction lens unit.

A scanning optical system (SL) comprises a first lens group (G1) having a negative refractive power, a second lens group (G2) having a positive refractive power, and a third lens group (G3) having a negative refractive power. At least one lens included in any of the first to the third lens groups has a positive refractive power, and satisfies the conditional expression “νd1>80”. At least one lens included in any of the first to the third lens group has a negative refractive power, and satisfies the conditional expression “νd2<50”. The scanning optical system satisfies the conditional expression “h max≥18.0 [mm]”.

According to the present invention, even if an azimuth angle synchronized to laser light scanning on each reflecting surface of a polygon mirror differs as a result of variations in the speed of rotation during one rotation, distance image data in which said differences are rectified can be generated. This laser radar device is provided with a rotation detecting means (boss S and photo-interrupter 3) which detects the rotational phase of a polygon mirror (P) at a plurality of detecting locations in a circumferential direction, and a correcting means (FPGA 11) which corrects distance image data on the basis of the detection results from the rotation detecting means, wherein the correcting means effects correction in such a way as to reduce a mutual discrepancy in an azimuth angle around an axis of rotation between data in a range scanned using one reflecting surface and data in a range scanned using another reflecting surface. The number of provided detecting locations is an integral multiple of the number of reflecting surfaces that are arranged in the circumferential direction of the polygon mirror. A sector time period from detection at one detecting location to detection at the next detecting location is measured, and the correction amount is determined in accordance with the length of the sector time period.

Techniques are described for dynamically correcting image distortion during imaging of a patterned sample having repeating spots. Different sets of image distortion correction coefficients may be calculated for different regions of a sample during a first imaging cycle of a multicycle imaging run and subsequently applied in real time to image data generated during subsequent cycles. In one implementation, image distortion correction coefficients may be calculated for an image of a patterned sample having repeated spots by: estimating an affine transform of the image; sharpening the image; and iteratively searching for an optimal set of distortion correction coefficients for the sharpened image, where iteratively searching for the optimal set of distortion correction coefficients for the sharpened image includes calculating a mean chastity for spot locations in the image, and where the estimated affine transform is applied during each iteration of the search.