Spectra-physics Gmbh

Spectra Physics Lasers, Inc.

Other

Newport Corporation

Kevin K Holsinger

James D Kafka

Michael L Watts

Jan-Willem J Pieterse

Harold D DuBose

David L Wright

John P Ekstrand

Richard Boggy

David S Bell

Jianping Zhou

Olaf Korth

Dixon Kwok Chung

Ventzislav Stoev

Michael McNeal

Embodiments are directed to systems and methods for adjusting a wavelength, bandwidth or both. Such systems and methods may be applicable to laser beams within a laser cavity or amplifier. For some embodiments, such systems and methods may be used to allow a user to set a desired wavelength and bandwidth of a short pulse laser system for operation at those parameters without further adjustment by the user.

Automated bandwidth / wavelength adjustment systems and methods for short pulse lasers and optical amplifiers

A regenerative amplifier system that is optimized for low-gain gain media is provided. The system is configured to include a minimum number of intra-cavity elements while still eliminating the leakage of the seed pulses from the output beam. In addition, the contrast ratio of the amplified pulses is increased even considering the long build-up time that is required in low-gain regenerative amplifiers. This is accomplished using a single Pockels cell between the oscillator and amplifier to select a single seed pulse for the cavity, instead of using a Faraday isolator. This directs the unwanted seed pulses in a separate direction from the output pulse. When the amplified pulse exits the cavity, it is directed in a direction away from the oscillator by the same Pockels cell. Only one additional Pockels cell and one polarizer are required inside the regenerative amplifier cavity.

Low-gain regenerative amplifier system

Wavelength stability of an optical oscillator has been enhanced by feedback from an external position-sensing detector to control the position or tilt of an intracavity optical element, such as a mirror. The wavelength stability results from stabilization of the intracavity beam position relative to an aperture in the oscillator. The wavelength selectivity of the aperture results from incorporation of a dispersive element in the oscillator cavity that produces a mapping of wavelength to beam position at the aperture.

Wavelength locker

A laser system includes a pump source that produces a first output. The pump source has a feedback loop with a first summing junction and a first command that has step quantization or digitized set point. An output device is coupled to the pump source to receive the first output and produce a second output. A feedback loop is coupled to the first summing junction. The feedback loop includes a second summing junction coupled to at least a portion of the second output. The second summing junction receives a second command and provides an input to the first summing junction. The feedback loop reduces the step quantization from the first output to provide finer control step of a property of the second output.

System for improved power control

A laser includes a laser head and a power supply. At least two resonator mirrors define a resonator cavity. A gain medium is positioned in the resonator cavity. A temperature controller is positioned in the laser head and is coupled to the gain medium. The temperature controller maintains the gain medium at a temperature of 25 degrees C. or greater. A pump source supplies a pump beam to the gain medium and producing an output beam. The power source is coupled to the pump source.

Laser with temperature controller positioned in laser head

A synchronously pumped optical parametric oscillator (OPO) using a temperature tuned 90 degree phase matched LBO crystal is disclosed which provides a broad selection of output wavelengths. In one embodiment a Ti:sapphire pump source having a cavity length matched to the OPO cavity length pumps a cavity with an LBO crystal located at the cavity waist of the cavity mode. Resources are included to, tune the OPO to a desired wavelength, repetitively scan through a series of desired wavelengths, and adjust the cavity length to obtain a synchronous pumping condition and diagnose a wavelength at which the OPO is operating. A frequency doubled beam in the LBO crystal is generated as a substantially collinear alignment beam.

Synchronously pumped sub-picosecond optical parametric oscillator

A servo controlled laser system is provided which provides a laser output beam having reduced optical noise. The laser system may be any type of laser system and preferably is an ion laser system. The servo controlled laser system includes a laser head providing a laser output beam and a power driver coupled to the laser head which supplies input power to the laser head. The laser system also includes a light detector in the path of the output beam which generates an alternating current signal in response to the amount of optical noise detected in the laser output beam. A signal amplifier is coupled to the light detector for receiving and amplifying the alternating current signal. A wire couples the signal amplifier to power driver compensator circuitry which receives the amplified alternating current signal from the wire and, in response, adjusts the input power to reduce optical noise. In instances where a length of the wire is positioned sufficiently near an electrically noisy environment such that the electrically noisy environment modifies the amplified alternating current signal, the significance of the modification to the amplified alternating current signal is reduced by amplifying the alternating current signal prior to exposing the alternating current signal to the electrically noisy environment, thereby enabling a significant reduction in the optical noise present in the laser output beam. A method for producing a laser output beam having reduced optical noise is also provided using the servo controlled laser system.

Optical noise reduction circuitry for laser systems

A controller including a closed loop servo system for a laser, or other entity is capable of substantial reductions in predictable, periodic noise such as the line noise induced by the source of alternating current electrical power, and in random noise as well. The servo circuit includes resources which develop a stored version of the predictable noise and uses the stored version of the predictable noise to compensate for the predictable noise. According to another aspect, the servo circuit includes resources which automatically adjust loop gain as gain in the entity being controlled and the loop as a whole system varies. The resources which generate the stored version of the predictable noise may be operated in either analog or digital formats. The sampling resources include, in an analog/digital embodiment, a plurality of charge holding devices, Multiplexing circuitry is coupled to the charge holding devices, and connects a selected charge holding device to a sample node which receives the feedback signal. Control circuits control the multiplexing circuitry to switch, in sequence, the plurality of charge holding devices to the sampling node in synchronism with the predictable periodic noise so that a stored version is developed in the plurality of charge storage devices. In addition, the servo circuit includes resources which automatically adjust loop gain as the slope of the laser system varies, which substantially reduces both random and periodic noise.

Noise rejection circuitry and laser system using the same

Phase-locking means are provided for synchronizing the pulse timing of two (or more) passively mode-locked pulsed lasers. The phase-locking is carried out at a frequency much higher than that of the fundamental repetition rate of the lasers because it results in much higher sensitivity. The signal from the two bandpass filters is applied to a phase detector. A phase-locked loop circuit ('PLL') is employed to generate an error signal which is applied to a piezoelectric transducer ('PZT') attached to a mirror in one of the laser cavities. Corrections in the position of the mirror driven by the error signal help reduce the effects of phase noise in the relative fundamental repetition frequencies of the two lasers so that they are effectively synchronized with one another with a 'jitter' of less than 1 ps.

Apparatus and method for improved time synchronization of pulsed laser

A synchronously pumped optical parametric oscillator (OPO) using a temperature-tuned 90.degree. phase matched LBO crystal is disclosed which provides a broad selection of output wavelengths. A Ti:Sapphire pump source having a cavity length matched to the OPO cavity length pumps a cavity with an LBO crystal located at the cavity waist of the cavity mode.

A switched resistor regulator is constructed whose duty cycle response is nonlinear with small changes in input control voltage. Specifically, the response of a pulse-width modulator is made to increase less than linearly with small changes in input control voltage. In a preferred embodiment, the pulse-width modulator is altered by comparing the input control voltage with a nonlinear reference signal, rather than the substantially linear reference signal which is used in prior art pulse-width modulators. Specifically, the nonlinear reference signal may be generated by a nonlinear reference voltage circuit, such as an RC charging circuit, or such as a D/A converter controlled by a clocked programmable microprocessor.

Feedback loop gain compensation for a switched resistor regulator

An apparatus and method for eliminating integrator windup in control systems having a control input, a feedback signal and an actuator that can saturate in response to dynamic non linearities such as slew rate limits. The apparatus of the invention is comprised of circuitry that determines the rate of change of the output of the integrator and compares it to predetermined maximum allowable rates of change. If these maximum allowable rates of change have been exceeded, the comparator circuitry generates a compensation error signal which when combined with normal error signal integrated by the compensator tends to reduce the rate of change on the output of the integrator.

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Menlo Park, CA, United States of America

Kevin K Holsinger