A solid-state laser device includes a laser rod made of an alexandrite crystal; a flash lamp that outputs excitation light for exciting the laser rod, a glass tube for a lamp being made of quartz glass that at least blocks deep ultraviolet light having a wavelength of 200 nm to 300 nm, and transmits visible light having a wavelength of 400 nm or more; and a laser chamber that contains a tubular reflector that includes a hole part containing at least a portion of the laser rod or a portion of the flash lamp and is made of a porous material of polytetrafluoroethylene, an inner wall surface of the hole part being as a reflecting surface that reflects the excitation light.

Provided is a solid-state laser device in which a linear resonator including an output mirror and a rear mirror, a laser rod, and optical members are provided on a common base and are contained in a housing having the base as a portion. A holding part is provided to hold an excitation light source that extends parallel to the laser rod on a side of the laser rod opposite to the base. The optical members including a Q-switch are disposed between the laser rod and the rear mirror. An upper end position of the output mirror is at a position lower than a lower end position of the excitation light source held by the holding part, with the base as a reference. The holding part holds the excitation light source so as to be capable of being inserted and extracted with respect to the output mirror side in a longitudinal direction of the excitation light source.

Disclosed are a laser device which uses alexandrite crystal and is capable of suppressing abnormal oscillation even if the size thereof is reduced and suppressing damage to an AR coating on a Q switch or alexandrite crystal, and a photoacoustic measurement device. A laser rod 11 includes alexandrite crystal. A flash lamp 12 irradiates the laser rod 11 with excitation light. A resonator includes a pair of mirrors 14 and 15 with the laser rod 11 sandwiched therebetween. A Q switch 16 is inserted into the optical path of the resonator and controls the Q value of the resonator. A polarizer 17 is inserted into the resonator and is a non-coated Brewster polarizer which selectively transmits light in a predetermined polarization direction among light emitted from the laser rod.

In a laser device and a photoacoustic measurement device including the laser device, the intensity of light at each wavelength made independently controllable. The laser device includes a laser medium which has oscillation wavelengths at a first wavelength and a second wavelength with higher light emission efficiency than at the first wavelength, an excitation section, a first resonator, a second resonator, a Q-value change unit, and a control section. The control section oscillates light having the first wavelength through Q switching when a first delay time has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the first wavelength, and oscillates light having the second wavelength through Q switching when a second delay time has elapsed after the excitation of the laser medium has been started in a case where the oscillation wavelength is the second wavelength.

A Q switch is vibrated by applying a first voltage, and pulsed laser light is emitted by applying a second voltage to the Q switch at a point in time at which a preset delay time has passed from the start of emission of excitation light. Then, in this case, a time which is within a period, for which the vibration of the Q switch continues, and at which the intensity of the pulsed laser light periodically changing due to the vibration of the Q switch is maximized in a case where a point in time of application of the second voltage to the Q switch is changed is set as the delay time.

In a laser device that emits pulsed laser light by emitting excitation light to a laser medium in a state in which a first voltage is applied to a Q switch and changing the voltage applied to the Q switch from a first voltage to a second voltage after the emission of the excitation light, the application start timing of the first voltage during a normal operation is set to a timing at which the intensity of the pulsed laser light periodically changing due to the vibration of the Q switch is maximized.

The present application discloses various embodiments of a high peak power laser system which includes a diode pump source configured to directly pump at least one optical crystal positioned within the laser cavity, the diode pump source emitting at least one pump beam comprised of two or more vertically stacked optical signals having a wavelength from about 400 nm to about 1100 nm., the optical crystal configured to output at least one optical output having a wavelength of about 750 nm to about 1100 nm and having an output power of about 25 kW or more.

A MOPA laser system that includes a seed laser configured to output pulsed laser light, an amplifier configured to receive and amplify the pulsed laser light emitted by the seed laser; and a pump laser configured to deliver a pump laser beam to both the seed laser and the amplifier and a variable attenuator configured to eliminate missing Q-switched pulses.

A MOPA laser system that includes a seed laser configured to output pulsed laser light, an amplifier configured to receive and amplify the pulsed laser light emitted by the seed laser; and a pump laser configured to deliver a pump laser beam to both the seed laser and the amplifier.

A semiconductor distributed Bragg reflector (DBR) including a first multilayer structure including a plurality of first semiconductor layers and one or more second semiconductor layers each interposed between a corresponding pair of the plurality of first semiconductor layers; a second multilayer structure including a plurality of third semiconductor layers and one or more second semiconductor layers each interposed between a corresponding pair of the plurality of third semiconductor layers; and a protection layer interposed between the first multilayer structure and the second multilayer structure. The second semiconductor layer has a lower decomposition temperature than the first semiconductor layer. The third semiconductor layer has a lower decomposition temperature than the second semiconductor layer.