Methods for optical amplified imaging using a two-dimensional spectral brush
An apparatus and method for ultrafast real-time optical imaging that can be used for imaging dynamic events such as microfluidics or laser surgery is provided. The apparatus and methods encode spatial information from a sample into a back reflection of a two-dimensional spectral brush that is generated with a two-dimensional disperser and a light source that is mapped in to the time domain with a temporal disperser. The temporal waveform is preferably captured by an optical detector, converted to an electrical signal that is digitized and processed to provide two dimensional and three dimensional images. The produced signals can be optically or electronically amplified. Detection may be improved with correlation matching against a database in the time domain or the spatial domain. Embodiments for endoscopy, microscopy and simultaneous imaging and laser ablation with a single fiber are illustrated.
1. A method of optical imaging, comprising:
generating a two-dimensional spectral brush by directing a beam of light through a fiber collimator, beam expander and cylindrical lens to a first coarse disperser and a fine disperser onto a sample;
modulating light beams from the two-dimensional spectral brush transmitted through the sample with a spatial light modulator;
transmitting modulated light beams through a second coarse disperser and a second fine disperser to produce a modified beam;
refining the modified beam for detection by passing it through a cylindrical lens, telescope, fiber collimator, optical amplifier, pulse picker, optical filter, pumped dispersive fiber and second amplifier to produce a transmitted spatial brush encoding spatial information of the sample to provide a transmitted spectral brush;
decoding the transmitted spectral brush to provide an electric signal; and
processing said electric signal to retrieve a two-dimensional image.
2. A method as recited in claim 1 , wherein said first disperser and said second disperser are identical.
3. A method as recited in claim 1 , further comprising matching optically detected signals with an image database with a 1-bit quantizer.
4. A method as recited in claim 1 , further comprising reflecting the transmitted spectral brush with a mirror.
5. A method as recited in claim 1 , wherein said beam of light is produced by a light source selected from group of light sources consisting of an incoherent light source, a broadband pulse laser light source and a swept frequency continuous-wave laser light source.
6. A method as recited in claim 1 , wherein said decoding comprises:
performing a Dispersive Fourier Transformation on broadband laser pulses to provide temporal waveform;
capturing said waveform;
digitizing said captured waveform to provide a digital signal; and
processing the digital signal to produce an image.