Danmarks Tekniske Universitet

University of California

Esko-graphics A/s

Paul Michael Petersen

Peter Eskil Andersen

Ole Bjarlin Jensen

Lance Kriegsfeld

Ngoc Mai Thi Nguyen

Jes Broeng

Birgitte Thestrup Nielsen

Anders Kragh Hansen

Ole Jensen Bjarlin

André Müller

In certain embodiments a light therapy system (e.g., phototherapy device), such as for treatment of Alzheimer's disease, depression, dementia, short-term memory, or for improved learning, improved athletic performance or improved cognitive performance, is provided where the light system comprises a blue light source that operates at a frequency in the range from 20 to 50 Hz (preferably around 40 Hz), whereby the system enables retinal ganglion cells of a human to be exposed in order to stimulate brain waves (gamma oscillations in the human's brain).

Light therapy system and methods of use

The present invention relates to an apparatus comprising a diode laser () providing radiation in a first wavelength interval, a radiation conversion unit () having an input and an output, the radiation converter configured to receive the radiation in the first wavelength interval from the diode laser at the input, the radiation conversion unit configured to convert the radiation in the first wavelength interval to radiation in a second wavelength interval and the output configured to output the converted radiation, the second wavelength interval having one endpoint outside the first wavelength interval. Further, the invention relates to a method of optically pumping a target laser () in a laser system, the laser system comprising a laser source providing radiation at a first frequency, the laser source being optically connected to an input of a frequency converter, the frequency converter configured to convert the radiation at the first frequency to a second, different frequency, the target laser arranged in optical communication with an output of the frequency converter, the method comprising the steps of emitting radiation from the laser source, receiving the radiation at the frequency converter, converting the radiation from the first frequency to the second frequency in the frequency converter, and providing the radiation at the second frequency at the target laser so that the target laser is optically pumped.

Laser system with wavelength converter

A laser apparatus generating frequency converted light. Embodiments of the laser apparatus described herein apply a cascade of nonlinear frequency mixer for sum frequency generation (SFG) or difference frequency generation (DFG) between two frequency components of a spectrally combined laser beam with at least two spectral components originating from two respective laser sources, SFG of two frequency components beams offers up to a factor of four amplification of output power over SHG of a single laser beam.

Laser apparatus with cascade of nonlinear frequency mixers

A method of controlling beam quality and stability of a laser apparatus, the laser apparatus comprising, a diode laser () providing first radiation of at least a first wavelength, and a frequency conversion unit () configured to frequency-convert the first radiation from the diode laser and to output the frequency-converted radiation (), the frequency-converted radiation having at least a second wavelength different from the first wavelength, the diode laser () comprising at least a first and a second section (), a first contact () for injecting a first current (I) into the first section (), a second contact () for injecting a second current (I) into the second section (), and means for controlling a temperature of the diode laser; wherein the method comprises monitoring a first parameter indicative of the power content of a dominant lobe of the first radiation; iteratively determining a combination of respective values of the first current, the second current and the temperature at which combination of respective values the monitored first parameter and a stability parameter indicative of a fluctuation over time of the monitored first parameter each fulfills a respective predetermined optimization criterion; and setting the first current, the second current, and the temperature to the determined combination of respective values.

The present invention relates to an apparatus comprising a diode laser () providing radiation in a first wavelength interval, a radiation conversion unit () having an input and an output, the radiation converter configured to receive the radiation in the first wavelength interval from the diode laser at the input, the radiation conversion unit configured to convert the radiation in the first wavelength interval to radiation in a second wavelength interval and the output configured to output the converted radiation, the second wavelength interval having one end point outside the first wavelength interval. Further, the invention relates to a method of optically pumping a target laser () in a laser system, the laser system comprising a laser source providing radiation at a first frequency, the laser source being optically connected to an input of a frequency converter, the frequency converter configured to convert the radiation at the first frequency to a second, different frequency, the target laser arranged in optical communication with an output of the frequency converter, the method comprising the steps of emitting radiation from the laser source, receiving the radiation at the frequency converter, converting the radiation from the first frequency to the second frequency in the frequency converter, and providing the radiation at the second frequency at the target laser so that the target laser is optically pumped.

Disclosed is a laser system that comprises a laser source adapted to emit a laser beam, wherein the laser source comprises a plurality of emitters for emitting respective beam contributions to the emitted laser beam; and first and second feedback means adapted to provide optical feedback to respective first and second parts of the emitted laser beam. The first feedback means is adapted to predominantly feed back a respective angular/directional contribution of each of said beam contributions into a corresponding one of the plurality of emitters from which said angular/directional contribution was emitted at a predetermined output angle, to cause each of the plurality of emitters to predominantly emit a beam contribution towards the second feedback means at an angle corresponding to the predetermined output angle.

Segmented diode laser system

Disclosed is a laser system comprising: A laser assembly () comprising a plurality of emitters; first and second light feedback devices () forming respective external cavities with the laser assembly; a dispersive device () for redirecting respective portions of the light from the laser assembly to the first and second feedback devices (), wherein the first feedback device () is adapted to reflect a feedback portion of the redirected beam back onto the dispersive device () and to generate the output beam () from an output part of the first redirected beam, &#x2014;an imaging device () for generating an optical Fourier transform of the plurality of emitters at a Fourier plane (). The dispersive device () is positioned displaced from said Fourier plane () by a predetermined displacement (d) in a direction along said principle axis ().

Laser system with segmented diode laser

A diode laser system having a diode amplifier member with a large transverse gain area. The diode amplifier member includes an amplifying medium for amplifying a number of spatial modes of a spatial light distribution. The laser system further includes a number of passive reflective members forming a laser cavity which includes at least a part of the diode amplifier member, each of the passive reflective members being adapted, during operation, to reflect light at least partially into the amplifying medium. The passive reflective members are adapted, during operation, to induce, via the light reflected by them, a self-induced dynamic gain and refractive index grating in the diode amplifier member, the dynamic gain and refractive index grating selecting one of said spatial modes and suppressing at least a part of the remaining spatial modes of the spatial light distribution.

High-power diode laser system

A diode laser system providing a high-power laser beam with good spatial coherence, which can be focused to a small spot size over long distances and which has a good pointing stability. The laser system comprises a laser diode () adapted to emit a first light beam, where the first light beam comprises a plurality of spatial modes, selection means () adapted to select a predetermined part of the first light beam, and a reflector (), where the laser diode and the reflector define a cavity and where the reflector is adapted to reflect the selected part of the first light beam back into the laser diode as a second light beam. The laser system is characterised in that the selection means is adapted to select a part of the first light beam corresponding to a spatial mode with a higher mode number than a spatial mode with maximum gain.

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Hillerød, Denmark

Paul Michael Petersen