Abstract:
In various embodiments, wavelength beam combining laser systems incorporate optics having optical power along the non-WBC direction (and/or the slow-diverging axis) of the combined multi-wavelength beam proximate to or combined with the partially reflective output coupler in order to correct pointing variation in the non-WBC direction (and/or the slow-diverging axis).
Abstract:
A method and apparatus for stabilizing the seed laser in a laser produced jplasma (LPP) extreme ultraviolet (EUV) light system are disclosed, In one embodiment, the cavity length of the laser may be adjusted by means of a movable mirror forming one end of the cavity. The time delay from the release of an output pulse to the Jasing threshold next being reached is measured at different mirror positions, and a mirror position selected which results in a cavity mode being aligned with the gain peak of the laser, thus producing a minimum time delay from an output pulse of the laser to the next lasing threshold, A Q- switch in the laser allows for pre-lasing and thus jitter-free timing of output pulses. Feedback loops keep the laser output at maximum gain and efficiency, and the attenuation and timing at a desired operating point.
Abstract:
Methods, systems, and computer-readable media are provided for operating a vertical-cavity surface-emitting laser. Operating a vertical-cavity surface-emitting laser can include sending a signal to a driver to decrease an optical power of a vertical cavity surface emitting laser transmitter, and sending a signal to the driver associated with increasing the optical power by a particular amount in response to determining that the optical power is insufficient for reception by a receiver.
Abstract:
There is provided a frequency tunable laser system (1) comprising a laser, frequency varying means (6) arranged for varying an optical frequency output of the laser (2), an intensity sensor (7m) arranged for receiving light (5b) from the laser (2), and a processor (8) arranged for controlling the frequency varying means (6) for varying the optical frequency output of the laser (2) and receiving an intensity signal (Sm) from the intensity sensor (7m) for monitoring the intensity output of the laser (2). The frequency tunable laser system (1) further comprises an external reflective surface (9), in use, fixedly arranged in a light path of the laser beam (5) outside the laser cavity (9) at a predefined distance (L) from the second reflective surface (2b) along the light path of the laser beam (5) to reflect part (5') of the emitted laser beam (5) back into the laser cavity (9). The processor (8) is further arranged for processing the intensity signal (Sm) and registering oscillations of the intensity output (I) caused by interference of the reflected part (5') of the laser beam (5) in the cavity (9) and responsive to a change in optical frequency and calculating the change in optical frequency output from the registered oscillations of the intensity output and predefined distance (L).
Abstract:
There is described a laser assembly for providing light at a switchable output wavelength. The assembly comprises first and second tuneable lasers (101, 201), each configurable to emit light at a laser wavelength chosen from a range of wavelengths. Light is transmitted from the first laser while the second laser is retuned to change the chosen laser wavelength thereof. Each laser comprises one or more thermally sensitive control components for controlling the operation of the laser and an additional component electrode (104, 204) located adjacent to at least one of the one or more control components (103, 203). The laser is configured so that the sum of electrical currents supplied to each control component (103, 203) and its corresponding additional component (104, 204) remains substantially constant in use. Switching from one laser to the other may be realized by monolithically integrated SOA (108, 208) with adjacent dummy SOA (109, 209) to keep the thermal load of the assembly constant and to prevent a thermal drift after wavelength switching.
Abstract:
According to aspects of an embodiment of the disclosed subject matter, a line narrowed high average power high pulse repetition laser micro-photolithography light source bandwidth control method and apparatus are disclosed which may comprise a bandwidth metrology module measuring the bandwidth of a laser output light pulse beam pulse produced by the light source and providing a bandwidth measurement; a bandwidth error signal generator receiving the bandwidth measurement and a bandwidth setpoint and providing a bandwidth error signal; an active bandwidth controller providing a fine bandwidth correction actuator signal and a coarse bandwidth correction actuator signal responsive to the bandwidth error. The fine bandwidth correction actuator and the coarse bandwidth correction actuator each may induce a respective modification of the light source behavior that reduces bandwidth error. The coarse and fine bandwidth correction actuators each may comprise a plurality of bandwidth correction actuators.
Abstract:
A smart laser having automatic computer control of pulse energy, wavelength and bandwidth using feedback signals from a wavemeter. Pulse energy is controlled by controlling discharge voltage, wavelength by controlling the position of an RMAX mirror and bandwidth is controlled by adjusting the curvature of a grating (82) to shapes more complicated than simple convex or simple concave. A preferred embodiment provides seven piezoelectric driven pressure-tension locations(84) on the back side of the grating(82) at 5 horizontal locations to produce shapes such as S shapes, W shapes and twisted shapes. Preferred embodiment include automatic feedback control of horizontal and vertical beam profile by automatic adjustment of a prism plate on which beam expander prisms are located and automatic adjustment of the RMAX tilt.
Abstract:
A light source (16) comprises a light producing unit (160) having a single wavelength producing light source (160A) and a light modulator (160c) for converting light from the light source to an optical pulse and outputting the optical pulse, an optical amplifying unit (161) having a group of optical fibers each provided with a fiber amplifier for amplifying the optical pulse from the light modulator, and a light intensity control unit (16c). The light intensity control unit (16c) controls stepwise the intensity of light outputted from each optical fiber by turning on/off the output separately and controls the intensity of light such as at least either the control of frequency of the optical pulse from the light modulator or the peak power thereof. Therefore it is possible to adjust minutely the intensity of light at each stage, in addition to the stepwise control of intensity of light, by controlling at least either the frequency of the optical pulse or the peak power thereof, thereby enabling the intensity of light to be controlled to any preset intensity if the intensity of light is in a predetermined range.