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.

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 fingerprint sensor-compatible overlay material which uses anisotropic conductive material to enable accurate imaging of a fingerprint through an overlay is disclosed. The anisotropic conductive material has increased conductivity in a direction orthogonal to the fingerprint sensor, increasing the capacitive coupling of the fingerprint to the sensor surface, allowing the fingerprint sensor to accurately image the fingerprint through the overlay. Methods for forming a fingerprint sensor-compatible overlay are also disclosed.

A multiple cavity laser system includes: a controller configured to operate the system as well as a plurality of laser cavities, each of the laser cavities having an output end wherein, when activated by the controller, an output laser beam is emitted from the output end of each of the laser cavities. The output laser beams when activated are directed, either directly or indirectly, to a rotating mirror. The rotating mirror is operatively connected to the controller and a servo motor. The servo motor, under direction of the controller, redirects the output laser beams along a common optical axis and the output laser beams of the plurality of laser cavities are combined along the common optical axis.

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.

A laser system includes a first laser source with a laser resonator for generating a first pulsed laser beam. The resonator has a back mirror, an outcoupling mirror and an active lasing medium in between. The system includes a second laser source for generating a second pulsed laser beam and an optical block. The optical block includes a coupling polarizer and a first polarization rotator. The optical block is movable back and forth between an active position and a passive position. In its active position the optical block is located between the outcoupling mirror and the active lasing medium such that the coupling polarizer couples the second beam into the laser resonator of the first laser source while the first rotator is positioned between the outcoupling mirror and the coupling polarizer. In the active position of the optical block a second polarization rotator is between it and the back mirror.

A laser system includes a first laser source with a laser resonator for generating a first pulsed laser beam. The resonator has a back mirror, an outcoupling mirror and an active lasing medium in between. The system includes a second laser source for generating a second pulsed laser beam and an optical block. The optical block includes a coupling polarizer and a first polarization rotator. The optical block is movable back and forth between an active position and a passive position. In its active position the optical block is located between the outcoupling mirror and the active lasing medium such that the coupling polarizer couples the second beam into the laser resonator of the first laser source while the first rotator is positioned between the outcoupling mirror and the coupling polarizer. In the active position of the optical block a second polarization rotator is between it and the back mirror.

Disclosed herein is a single pulse laser apparatus which includes a first mirror and a second mirror disposed at both ends of the single pulse laser apparatus and having reflectivities of a predetermined level or more; a gain medium rotated at a predetermined angle and configured to oscillate a laser beam in a manual mode-locking state; a linear polarizer configured to output a beam having a specific polarized component of the oscillated laser beam; an etalon configured to adjust a pulse width of the oscillated laser beam; and an electro-optic modulator configured to perform Q-switching and single pulse switching.