42 results about "Nonlinear scattering" patented technology

Methods of acoustic imaging provide images with reduced reverberation noise and images of nonlinear scattering and propagation parameters of the object, and estimation methods of corrections for wave front aberrations produced by spatial variations in the acoustic propagation velocity. The methods are based on processing of the received signal from transmitted dual frequency band acoustic pulse complexes with overlapping high and low frequency pulses. The high frequency pulse is used for the image reconstruction and the low frequency pulse is used to manipulate the nonlinear scattering and / or propagation properties of the high frequency pulse. Through filtering in the pulse number coordinate and corrections for nonlinear propagation delays and optionally also amplitudes, a linear back scattering signal with suppressed pulse reverberation noise, a nonlinear back scattering signal, and quantitative nonlinear forward propagation and scattering parameters are extracted.

Elastic wave pulse complexes are transmitted towards said region where said pulse complexes are composed of a high frequency (HF) and a low frequency (LF) pulse with the same or overlapping beam directions and where the HF pulse is so close to the LF pulse that it observes the modification of the object by the LF pulse at least for a part of the image depth. Received HF signals are picked up by transducers from scattered and / or transmitted components of the transmitted HF pulses. The received HF signals are processed to form measurement or image signals for display, and combined in slow time to form noise suppressed HF signals or nonlinear scattering HF signals.

The present invention is directed to a method of applying radiation through an optical fiber for detecting disease within a plant or animal or other penetrable tissue, or imaging a particular tissue of a plant or animal. In addition, fluorescence and nonlinear scattering signals can be detected and localized within a subject by such application of radiation through an optical fiber. The radiation is effective to promote simultaneous multiphoton excitation. The optical fibers are used alone to examine internal regions of tissue, in conjunction with an optical biopsy needle to evaluate sub-surface tissue, or with an endoscope to evaluate tissue within body cavities. The present invention also relates to a device for coupling in radiation from an ultrashort mode-locked laser into the beam path of a microscope.

Measurement or imaging of elastic wave nonlinear scatterers with a memory of scattering parameters comprises selecting LF pulses having characteristics to change the scattering parameters of nonlinear scatterers. A transmit time relation is selected so that the incident HF pulse propagates sufficiently close to the LF pulse that the effect of the incident LF pulse on its scatterer parameters is observed by the HF pulse. At least two elastic wave pulse complexes comprising a high frequency (HF) pulse and a selected low frequency (LF) pulse are transmitted towards the region. Received HF signals are combined to form nonlinear HF signals representing the scatterers with memory, with suppression of received HF signals from other scatterers. At least one of the received HF signals may be corrected by time delay correction and / or speckle correction with a speckle correction filter, determined by movement of the scattering object. Systems are also disclosed.

New methods of ultrasound imaging are presented that provide images with reduced reverberation noise and images of nonlinear scattering and propagation parameters of the object, and estimation of corrections for wave front aberrations produced by spatial variations in the ultrasound propagation velocity. The methods are based on processing of the received signal from transmitted dual frequency band ultrasound pulse complexes with overlapping high and low frequency pulses. The high frequency pulse is used for the image reconstruction and the low frequency pulse is used to manipulate the nonlinear scattering and / or propagation properties of the high frequency pulse. A 1st method uses the scattered signal from a single dual band pulse complex for filtering in the fast time (depth time) to provide a signal with suppression of reverberation noise and with 1st harmonic sensitivity and increased spatial resolution. In other methods two or more dual band pulse complexes are transmitted where the frequency and / or the phase and / or the amplitude of the low frequency pulse vary for each transmitted pulse complex. Through filtering in the pulse number coordinate and corrections of nonlinear propagation delays and optionally also amplitudes, a linear back scattering signal with suppressed pulse reverberation noise, a nonlinear back scattering signal, and quantitative nonlinear scattering and forward propagation parameters are extracted. The reverberation suppressed signals are further useful for estimation of corrections of wave front aberrations, and especially useful with broad transmit beams for multiple parallel receive beams. Approximate estimates of aberration corrections are given. The nonlinear signal is useful for imaging of differences in tissue properties, such as micro-calcifications, in-growth of fibrous tissue or foam cells, or micro gas bubbles as found with decompression or injected as ultrasound contrast agent.

A system and method for integrating a direct compressor with a primary laser source and fast compressor while also reducing the number of mechanical elements and gas interfaces. A nonlinear scattering aperture combiner does not need to be optically multiplexed in order to drive a direct compressor stage, but by producing a large temporal compression ratio it will then pump the fast compressor. In order to accomplish this, a technique for transversely segmenting by color and / or polarization of the optical extraction beams of the direct compressor is utilized.

The invention relates to the technical field of surface coatings, nonlinear optics and laser protection, in particular to a broadband laser protection method and structure. The broadband laser protection structure is obtained through the series of steps of preparation of vanadium pentoxide, design of a sapphire shell, preparation of carbon nanotube suspension liquid, and injection and sealing of the suspension liquid. The broadband laser protection structure is widely applied to the technical field of optic intelligent windows and laser protection. The broadband laser protection structure is characterized in that composite multi-element protection is adopted, combined with wave band characteristics of existing various nonlinear optical limiting materials, intensive laser interference signals can be attenuated more effectively through thermally induced phase-transition optical limiting and nonlinear scattering methods, and therefore continuous and adjustable laser protection on the visible light wave band and the near infrared wave band is achieved. The method provided by the invention has the advantages that the process is simple, the rate of finished products is high, and the method is mature and reliable.