31results about How to "Avoid optical damage" patented technology

A modelocked linear fiber laser cavity with enhanced pulse-width control includes concatenated sections of both polarization-maintaining and non-polarization-maintaining fibers. Apodized fiber Bragg gratings and integrated fiber polarizers are included in the cavity to assist in linearly polarizing the output of the cavity. Very short pulses with a large optical bandwidth are obtained by matching the dispersion value of the fiber Bragg grating to the inverse of the dispersion of the intra-cavity fiber.

A wavelength converting device 1 has a substrate 5 made of an electro-optic material and converts a wavelength of a fundamental light to oscillate a converted light. A wavelength converting portion 7 is provided in the substrate 5 and has a cross sectional area of 0.0001 mm² or larger and 0.01 mm² or smaller. A pair of thinner portions 12A and 12B are provided in both sides of the wavelength converting portion, respectively, and thinner than the wavelength converting portion 7.

In a transmission type screen and other optical devices formed by combining optical sheets such as a Fresnel lens sheet and a lenticular lens sheet, the generation of stray light and defective appearance caused by a friction-reducing agent are prevented. In the optical devices such as a transmission type screen 3 formed by combining a plurality of optical sheets such as a Fresnel lens sheet 1 and a lenticular lens sheet 2, a friction-reducing agent 20 is provided on a surface of at least one of the optical sheets at a thickness of 0.3 nm or more to 10 nm or less. A coating applicator 30 for the friction-reducing agent 20 includes: a transfer roller 31; coating liquid-supplying means 32 for supplying the coating liquid 20 to the transfer roller 31; and scraping means 35 for adjusting the thickness of the coating liquid 20 adhering to the transfer roller 31. In the coating liquid 30, the surface roughness Ra (JIS B 0601-1982) of the transfer roller 31 is set to 0.01 to 1 μm.

The present invention discloses a stack type optical disk changer including a main frame, a cartridge slidably installed on the main frame, a plurality of disk trays slidably stacked in the cartridge, and a cartridge movement preventing means installed in the main frame, for selectively stopping movement of the cartridge. The stack type optical disk changer maintains quality of sound or image of an optical disk, and prevents damages of the optical disk, mis-operations and breakage, by preventing the optical disk from being separated from the tray.

An optical isolator for generally collimated laser radiation includes a single polarizing element, at least one Faraday optical element, at least one reciprocal polarization altering optical element disposed at the single polarizing element, at least one reflective optical element for reflecting radiation to provide an even number of passes through the at least one Faraday optical element, and a magnetic structure. The magnetic structure is capable of generating a magnetic field within the at least one Faraday optical element that is generally aligned with the even number of passes along a beam propagation axis. The optical isolator is configured to receive generally collimated laser radiation, which passes through the single polarizing element and the at least one reciprocal polarization altering optical element and which makes at least two passes through the at least one Faraday optical element, whereby generally collimated laser radiation is output from the optical isolator.

A lighting device, for illuminating display designed parts on a display plate, includes at least one light source arranged at a rear side of the display plate, and a light guide body having a light guide portion for guiding the light toward its outer-circumferential portion to output the light toward the display designed parts through a front surface of the light guide portion. The outer-circumferential portion has an outer-circumferential side wall surface at is outer end. The light guide portion has at least one projecting portion projecting from the outer-circumferential side wall surface. The projecting portion is provided with a reflecting side surface formed along the outer-circumferential side wall surface so that the reflecting side surface can reflect the light traveling in the light guide portion to be outputted through the front surface of the light guide portion.

An encapsulating sheet is formed from an encapsulating resin composition which contains an encapsulating resin and silicone microparticles, and the mixing ratio of the silicone microparticles with respect to the encapsulating resin composition is 20 to 50 mass %.

Provided is a terahertz wave generation method used to generate a terahertz wave in a direction that satisfies non-collinear phase matching conditions by inputting pump light into a non-linear opticalcrystal capable of generating the terahertz wave based on an optical parametric effect, wherein the pump light input into the non-linear optical crystal has a pulse width of 10 ps or greater and lessthan or equal to 1 ns with a repetition frequency of 1 kHz or greater, so that the peak excitation power density thereof is greater than or equal to a given terahertz wave oscillation threshold and less than or equal to a given laser damage threshold, and the average excitation power density thereof is less than or equal to a given photorefractive effect generation threshold.

The invention provides a picosecond seed source excitation device, which is characterized in that a resonant cavity is formed by two end surfaces of an Nd:YAG&Cr<4+>:YAG bonding crystal, the Nd:YAG&Cr<4+>:YAG bonding crystal (4) is used as a passive Q-switching crystal, the Q value of the resonant cavity is adjusted by using the saturable absorption characteristic of the Nd:YAG&Cr<4+>:YAG bonding crystal (4) so as to achieve the Q-switching purpose, a collimating mirror (2) and a focusing mirror (3) perform beam shaping on incident pump light so as to make the pump light enter the Nd:YAG&Cr<4+>:YAG bonding crystal (4) at a specific angle and position to form a focus point in the crystal, then the divergence angle of the light beam is shaped and compressed through a concave beam expander lens (6) and a convex beam expander lens (8), and the light beam can pass through an isolator (7) in one direction, so that the influence of the return light on the crystal and the optical fiber and irreversible optical damage are avoided, and the characteristics of high energy, narrow pulse width, high light beam quality, high stability and the like are achieved so as to improve the energy conversion efficiency, reduce the device loss and prolong the service life.