摘要:
Disclosed herein are devices and methods to provide multiple eyeboxes from multiple input pupils. In particular, a projection system can direct light from multiple input pupils to a holographic optical element. The light of each of the input pupils having light beams of different wavelengths. The holographic optical element reflects at least part of the light of the multiple input pupils to form an array of exit pupils.
摘要:
The invention disclosed here teaches methods to fabricate and utilize a non-dispersive holographic wavelength blocker. The invention enables the observation of the Raman signal near the excitation wavelength (˜9 cm−1) with the compactness of standard thin film/holographic notch filter. The novelty is contacting several individual volume holographic blocking notch filter (VHBF) to form one high optical density blocking filter without creating spurious multiple diffractions that degrade the filter performance. Such ultra-narrow-band VHBF can be used in existing compact Raman instruments and thus will help bring high-end research to a greater number of users at a lower cost.
摘要:
The invention disclosed here teaches methods and apparatus for altering the temporal and spatial shape of an optical pulse. The methods correct for the spatial beam deformation caused by the intrinsic DC index gradient in a volume holographic chirped reflective grating (VHCRG).The first set of methods involves a mechanical mean of pre-deforming the VHCRG so that the combination of the deflection caused by the DC index gradient is compensated by the mechanical deformation of the VHCRG. The second set of methods involves compensating the angular deflection caused by the DC index gradient by retracing the diffracted beam back onto itself and by re-diffracting from the same VHCRG. Apparatus for temporally stretching, amplifying and temporally compressing light pulses are disclosed that rely on the methods above.
摘要:
A method is presented for shaping the spectral response of volume holographic grating elements by applying controlled thermal energy. The methods allow generating continuous or discontinuous grating periods from a fixed grating period. The methods are applicable to optical feedback into optical sources such as light emitting diodes, lasers and other general optical filtering applications.
摘要:
The invention combines fluorescent QDs and methods to dispense and detect them efficiently in a compact volume for a range of optical tagging applications. Micro-fluidic devices are used for mixing water-soluble fluorescent QDs in aqueous solutions to create a multi color fluorescent nano-optical tag, and gratings are used for spreading the spectral components of the fluorescent signal leading to an improvement in optical data storage capacity over prior art methods. The spectral signature of the tag is detected by a compact read-out head with a grating spectrometer. One way is to dispense the tag within the pits of a DVD or CD using an ink-jet nozzle and exciting them by a large range of wavelengths each shorter that the emission peak. The filters have a high immunity to prolonged exposure to high temperatures, and up to 41 infrared filters can be holographically recorded by spatial multiplexing of the substrate.
摘要:
A laser utilizes feedback from a volume holographic grating integrated in a collimating lens as a wavelength standard to lock the laser output wavelength to its desired value. This feedback is optical, wherein a volume hologram reflection grating is used to generate optical feedback into the laser gain region. Fabrication of the integrated volume hologram grating lens elements is by either first recording the grating in a rectangular parallelepiped of material and then shaping the lens from it, or alternatively by first shaping the material into the desired shape and then recording the grating with the use of an apparatus composed of an optical block within which a cavity is present to accept the lens and index matching fluid.
摘要:
In the present invention, a volume holographic optical element is used as a pump coupler. The holographic coupler allows at least one pump wavelength to be coupled into the laser medium. The direction of the pump beam onto the coupler is not co-linear with the direction of the signal beam out of the coupler. The invention further provides the coupling of more than one pump wavelengths using a single holographic coupler element while maintaining the high isolation between pump and signal beam. The invention further provides a narrow-band reflection grating of various efficiencies for the signal beam (as part of the laser cavity).
摘要:
A laser utilizes feedback from a multiplexed volume holographic grating (VHG) as a stand alone element or integrated in a collimating lens as a wavelength standard to lock the laser output wavelength to its desired value. This feedback is optical, wherein a volume hologram reflection grating is used to generate optical feedback into the laser gain region. The multiplexed VHG can exhibit a variety of spectral bandwidth as a result of coherent superposition of the multiplexed gratings or the multiplexed VHG can replace individual VHGs that are used with several wavelength specific lasers.
摘要:
The present invention provides a multi-channel turnable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings imprinted into a filter material, such as Lithium Niobate. In another embodiment, the filter comprises a bank of gratings imprinted on a thin-film filter. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack In another embodiment, the gratings are recorded by a phase masking method.
摘要:
The invention combines fluorescent QDs and methods to dispense and detect them efficiently in a compact volume for a range of optical tagging applications. Micro-fluidic devices are used for mixing water-soluble fluorescent QDs in aqueous solutions to create a multi color fluorescent nano-optical tag, and gratings are used for spreading the spectral components of the fluorescent signal leading to an improvement in optical data storage capacity over prior art methods. The spectral signature of the tag is detected by a compact read-out head with a grating spectrometer. One way is to dispense the tag within the pits of a DVD or CD using an ink-jet nozzle and exciting them by a large range of wavelengths each shorter that the emission peak. The filters have a high immunity to prolonged exposure to high temperatures, and up to 41 infrared filters can be holographically recorded by spatial multiplexing of the substrate.