Abstract:
Apparatus and methods are described for determining information about at least one particle by measuring light scattered from the particles. Scattered light is detected from a region of a particle dispersion or from a larger region in a generally collimated illumination beam. Scattered light is also detected from a plurality of regions for improvement of repeatability.
Abstract:
A spatial splitting-based optical Micro Electro-Mechanical Systems (MEMS) Interferometer includes a spatial splitter for spatially splitting an input beam into two interferometer beams and a spatial combiner for spatially combining the two interferometer beams. A MEMS moveable mirror is provided to produce an optical path difference between the first interferometer beam and the second interferometer beam.
Abstract:
A method for correcting spatial response for an imaging Fourier transform spectrometer comprises the following steps: a prior step of calculation of the equalization parameters comprising a gain and an offset from data forming calibration scenes; a step of determination of equalization coefficients at a so-called pseudo superpixel level determining the gains and offsets at macropixel level from the data from a raw image that are collected by the imaging spectrometer in image mode, and gains and offsets determined in the prior step; and a step of equalization at pseudo superpixel level, applying the equalization coefficients to a macropixel from an acquisition in the interferogram mode of the imaging spectrometer in order to restore an equalized interferogram.
Abstract:
A Sagnac interferometer can include a beamsplitter arranged to receive an input beam of light of a design wavelength, to split the input beam of light into first and second beams that counter propagate around an optical path, and to recombine the first and second beams into an output beam of light. The optical path can include at least one diffraction grating that is arranged to satisfy an effective Littrow geometry.
Abstract:
A phase-locked delay device, including: an input port configured to receive an input electromagnetic radiation pulse; said input pulse being to be propagated along a propagation direction and having a first linear polarization different from both a first direction, which is orthogonal to the propagation direction, and a second direction, which is orthogonal to the first direction and the propagation direction; an adjustable Babinet-Soleil module optically coupled to said input port, having a first polarization direction parallel to said first direction. The adjustable Babinet-Soleil module is structured to: provide from the input pulse a first pulse polarized along the first direction and a second pulse collinear to said first pulse and polarized along the second direction, and introduce an adjustable group delay between the first pulse and the second pulse ranging from a minim value ΔTm and a maximum value ΔTM; the maximum value ΔTM being a value greater than 10 fs.
Abstract:
A method for facilitating in-device coexistence between radios is provided. The method can include a processor implemented on the wireless communication device defining a coexistence policy for a first radio and a second radio co-located on the wireless communication device; and providing the coexistence policy to a coexistence management controller on the first radio via an interface between the processor and the first radio. The method can further include the second radio providing state information for the second radio to the first radio via an interface between the first radio and the second radio. The method can additionally include the coexistence management controller on the first radio using the state information to control operation of the first radio in accordance with the coexistence policy to mitigate interference with the second radio.
Abstract:
A system and method for performing Raman spectroscopy using a heterodyne detection scheme are described. The heterodyne detection scheme can combine a modulated portion of radiation having passed through a sample to be analyzed with a reference radiation to produce a combined frequency signal. At least a portion of the reference radiation can be filtered out of the combined frequency signal, resulting in a filtered frequency signal. Information related to the sample can be determined based upon the filtered signal. The determined information can then be analyzed to determine a chemical composition of the sample.
Abstract:
There is provided a method for referencing and correcting the beating spectrum generated by the interference of the components of a frequency comb source. The proposed method allows monitoring of variations of a mapping between the source and the beating replica. This can then be used to compensate small variations of the source in Fourier transform spectroscopy or in any other interferometry application in order to overcome the accuracy and measurement time limitations of the prior art. Constraints on source stability are consequently reduced.
Abstract:
An emission can be obtained from a sample in response to excitation using a specified range of excitation frequencies. Such excitation can include generating a specified chirped waveform and a specified downconversion local oscillator (LO) frequency using a digital-to-analog converter (DAC), upconverting the chirped waveform via mixing the chirped waveform with a specified upconversion LO frequency, frequency multiplying the upconverted chirped waveform to provide a chirped excitation signal for exciting the sample, receiving an emission from sample, the emission elicited at least in part by the chirped excitation signal, and downconverting the received emission via mixing the received emission with a signal based on the specified downconversion LO signal to provide a downconverted emission signal within the bandwidth of an analog-to-digital converter (ADC). The specified chirped waveform can include a first chirped waveform during a first duration, and a second chirped waveform during a second duration.
Abstract:
Current apparatuses and methods for analysis of spectroscopic optical coherence tomography (SOCT) signals suffer from an inherent tradeoff between time (depth) and frequency (wavelength) resolution. In one non-limiting embodiment, multiple or dual window (DW) apparatuses and methods for reconstructing time-frequency distributions (TFDs) that applies two windows that independently determine the optical and temporal resolution is provided. For example, optical resolution may relate to scattering information about a sample, and temporal resolution may be related to absorption or depth related information. The effectiveness of the apparatuses and methods is demonstrated in simulations and in processing of measured OCT signals that contain fields which vary in time and frequency. The DW technique may yield TFDs that maintain high spectral and temporal resolution and are free from the artifacts and limitations commonly observed with other processing methods.