178 results about "Pulse operation" patented technology

An optical illuminator using Vertical Cavity Surface Emitting Laser (VCSEL) is disclosed. Optical modules configured using single VCSEL and VCSEL arrays bonded to a thermal submount to conduct heat away from the VCSEL array, are suited for high power and high speed operation. High speed optical modules are configured using single VCSEL or VCSEL arrays connected to a high speed electronic module on a common thermal submount or on a common Printed Circuit Board (PCB) platform including transmission lines. The electronic module provides low inductance current drive and control functions to operate the VCSEL and VCSEL array. VCSEL apertures are designed for a desired beam shape. Additional beam shaping elements are provided for VCSELs or VCSEL arrays, for desired output beam shapes and/or emission patterns. VCSEL arrays may be operated in continuous wave (CW) or pulse operation modes in a programmable fashion using a built-in or an external controller.

The invention is directed to a collector mirror for short-wavelength radiation based on a plasma. It is the object of the invention to find a novel possibility for managing the temperature of a collector mirror for focusing short-wavelength radiation generated from a plasma which allows an efficient thermal connection to be produced between the optically active mirror surface and a thermostat system without the disadvantages relating to space requirements or high-precision manufacture of the collector mirror. This object is met, according to the invention, in that the collector mirror has a solid, rotationally symmetric substrate which comprises a material with high thermal conductivity of more than 50 W/mK and in which channels for cooling and temperature management are incorporated in the substrate so that a heat transport medium can flow through directly and for rapidly stabilizing the temperature of the optically active mirror surface. Heat of transient temperature spikes which occur in pulsed operation for plasma generation at the mirror surface and which temporarily exceed the temperature average by a multiple is quickly dissipated.

An apparatus, method and associated fiber-laser architectures for high-power pulsed operation and pumping wavelength-conversion devices. Some embodiments generate blue laser light by frequency quadrupling infrared (IR) light from Tm-doped gain fiber using non-linear wavelength conversion. Some embodiments use a fiber MOPA configuration to amplify a seed signal from a semiconductor laser or ring fiber laser. Some embodiments use the frequency-quadrupled blue light for underwater communications, imaging, and/or object and anomaly detection. Some embodiments amplitude modulate the IR seed signal to encode communication data sent to or from a submarine once the modulated light has its wavelength quartered. Other embodiments transmit blue-light pulses in a scanned pattern and detect scattered light to measure distances to objects in a raster-scanned underwater volume, which in turn are used to generate a data structure representing a three-dimensional rendition of the underwater scene being imaged for viewing by a person or for other software analysis.

A macular pigment reflectometer is handheld, light, and portable. It can be provided as a part of a self-contained system. The self-contained system includes a docking station in which the macular pigment reflectometer is placed between uses. The docking station is used to recharge the battery of the handheld macular pigment reflectometer. The docking station also has one or more types of communication ports, such as one for a wired or wireless internet connection, through which the handheld macular pigment reflectometer can communicate with a computer or an electronic medical records system. The instrument operates in a pulsed operating mode wherein relative instrument-to-eye motion is reduced and, preferably, nearly eliminated. The handheld macular pigment reflectometer contains an on-board spectrometer which is designed to capture spectra in very short intervals of time. A trigger on the instrument allows for a rapid, intuitive, and sequential alignment followed by rapid data gathering.

Optical pump modules using VCSEL arrays are provided to pump optical gain media for achieving high power laser output in CW, QCW and pulse operation modes for operation. Low divergence and symmetric far-field emission from VCSELs are particularly suitable for compact arrays. VCSEL arrays configured as laser pump modules are operable at high temperatures with practically no degradation over a long period of time. VCSEL pump modules are adaptable for side- or end-pumping configurations to pump high power lasers in CW, QCW and pulse mode. Power output from VCSEL pump modules is scalable. Incorporating microlens arrays with the VCSEL arrays improve brightness of the pump modules. High power and high temperature operation of VCSEL modules make it suitable for making compact high power solid state lasers that are operable in small spaces such as, ignition of internal combustion engines, stationary power generation engines and pulsed detonation engines.

A contactor may operate to interrupt current in a circuit while the circuit is operating under load. A shunt is provided to by-pass surge power current around contacts to reduce arcing. The shunt includes a solid-state switch that may be operated in a series of pulses during movement of the contacts. The pulse control unit may detect a potential for arcing and then provide for periodic pulsing operation of the shunt. Because the solid-state switch may operate discontinuously, the contactor may be constructed with a switch that is selected on a basis of its pulse rating.

In an extreme ultra violet light source apparatus that exhausts debris including fast ions and neutral particles by the effect of a magnetic field, neutral particles emitted from plasma are efficiently ionized. The extreme ultraviolet light source apparatus includes: a plasma generating unit that generates plasma, that radiates at least extreme ultra violet light, through pulse operation; collective optics that collects the extreme ultra violet light radiated from the plasma; a microwave generating unit that radiates microwave through pulse operation into a space in which a magnetic field is formed to cause electron cyclotron resonance, and thereby ionizes neutral particles emitted from the plasma; a magnetic field forming unit that forms the magnetic field and a magnetic field for trapping at least ionized particles; and a control unit that synchronously controls at least the plasma generating unit and the microwave generating unit.

A laser system for medical treatment is disclosed which comprises a pump, wherein the laser system is adapted to be operated in pulsed operation so that at least one laser pulse of a temporally limited pulse duration (T_p) is generated. The generated laser pulse irradiates some part of the human or animal body so that a two-dimensional laser spot S is located on the top layer of the irradiated part of the human or animal body. The pump power of the pump of the laser system is modulated in such a way that the cumulative energy E_S(T_p/2) which is delivered by said laser pulse to said laser spot S during the first half of the pulse duration is less than 45% of the energy E_S(T_p) which is delivered by said laser pulse to said laser spot S during the entire pulse duration T_p.

A Laser system is disclosed which comprises a pump, wherein the laser system is adapted to be operated in pulsed operation so that at least one individual pulse of a temporally limited pulse duration (T₀) is generated, wherein the pulse ablates a material such that a debris cloud forms above the ablated material. Further, the pump power of the pump is modulated in such a way that the following three conditions are fulfilled: (1) the intensity of the pulse oscillates between maximum values and minimum values during the pulse duration, wherein the laser pulse comprises a plurality of intensity maxima I_max which occur at times {T_i, i=1, . . . N}; and a plurality of intensity minima I_min which occur at times {t_k, k=1, . . . (N−1)}, wherein the intensity does not vanish at the intensity minima; (2) the intensity oscillations of the laser pulse induce oscillations of the size of the debris cloud so that, during the pulse duration (T₀), there are at least two maxima of the size of the debris cloud which occur at times {t_j, J=1, . . . M} and which are located in between two intensity maxima of the laser pulse; and (3) at least 70 percent of the maxima of the size of the debris cloud occur near an intensity minimum of the pulse such that, for at least 70 percent of the maxima of the size of the debris cloud, the intensity of the pulse I(t_j) at the time of the maximum of the size of the debris cloud is smaller than I_min(t_k)+0.5× [I_max(T_i)−I_min(t_k)], wherein I_min(t_k) is the intensity minimum of the pulse which is closest to the maximum of the size of the debris cloud at time t_j and I_max(T_i) is the intensity maximum of the pulse which is closest to the maximum of the size of the debris cloud at time t_j.

Optical pump modules comprising VCSEL and VCSEL array devices provide high optical power for configuring fiber optic gain systems such as fiber laser and fiber amplifier particularly suited for high power operation. Pump modules may be constructed using two reflector or three reflector VCSEL devices optionally integrated with microlens arrays and other optical components, to couple high power pump beams to a fiber output port. The pump module having a fiber output port is particularly suited to couple light to an inner cladding of a double-clad fiber, often used to configure high power fiber laser and fiber amplifier. The pump modules may be operated in CW, QCW and pulse modes to configure fiber lasers and amplifiers using single end, dual end, and regenerative optical pumping modes. Multiple-pumps may be combined to increase pump power in a modular fashion without significant distortion to signal, particularly for short pulse operation.

A laser system for hard body tissue ablation has a pumped laser, wherein the laser system is operated in pulsed operation with several individual pulses of a temporally limited pulse length and wherein the individual pulses follow one another with temporal pulse spacing. The pumped laser has an inversion population remaining time, the inversion population remaining time being the time within which, in the absence of pumping, the remaining inversion population of the laser energy status is reduced by 90%. The pulse spacing is in the range of ≧50 μs and ≦ to the inversion population remaining time.

Temperature compensation circuits and methods for adjusting one or more circuit parameters of a power amplifier (PA) to maintain approximately constant Gain versus time during pulsed operation sufficient to substantially offset self-heating of the PA. Some embodiments compensate for PA Gain “droop” due to self-heating using a Sample and Hold (S&H) circuit. The S&H circuit samples and holds an initial temperature of the PA at commencement of a pulse. Thereafter, the S&H circuit generates a continuous measurement that corresponds to the temperature of the PA during the remainder of the pulse. A Gain Control signal is generated that is a function of the difference between the initial temperature and the operating temperature of the PA as the PA self-heats for the duration of the pulse. The Gain Control signal is applied to one or more adjustable or tunable circuits within a PA to offset the Gain droop of the PA.

A pulsed magnetic field is generated by a device having a magnet to be operated in pulse operation which contains at least one superconductive refrigerant-free winding that is disk-shaped or saddle-shaped. Also included is a refrigerating unit which has at least one cold head. A line system, having a refrigerant circulating in it according to a thermosiphon effect, thermally couples the winding to the cold head. The line system has a plurality of separate pipes lying next to one another. The pipes, open onto a common refrigerant distributor and closed at the other end, are thermally coupled to the surface of the disk-shaped or saddle-shaped winding.

Pulsed laser drivers are disclosed comprising Gallium Nitride (GaN) power transistors for driving diode laser systems requiring high current and fast pulses, such as laser drivers for LIDAR (Light Detection and Ranging) systems. Drivers are capable of delivering pulses with peak current ≥100 A, e.g. 170 A to provide high peak power, fast pulses with nanosecond rise times and nanosecond pulse duration, for driving multi-channel laser diode arrays with 40 A per channel for 120 W output per channel for a combined peak output of 480 W. For lower duty cycle, example driver circuits are disclosed comprising a high current power transistor for direct drive with drive assist. For higher duty cycle, example resonant driver circuits are disclosed comprising two high current power transistors. Implementation of resonant driver circuits with GaN technology provides fast charging for short pulse operation at higher repetition rates or for pulse code modulation.

An ECU transmits a pulsed operation command signal, indicating operation commands for an electric motor used as a VVT actuator, to an electric-motor EDU. The electric-motor EDU recognizes the combination of the direction in which the actuator should be operated (actuator operation direction) and the control mode based on the duty ratio of the operation command signal, and the rotational speed command value based on the frequency of the operation command signal. The electric-motor EDU controls the electric motor according to the control commands. The duty ratio indicating the combination is set such that even if the duty ratio is falsely recognized, a false recognition concerning the actuator operation direction is prevented, such false recognition causing the valve phase to change in an undesirable direction, and even if the actuator operation direction is falsely recognized, the rate of change in the phase is restricted.