A three-dimensional object is imaged by providing a coherent beam of light with a periodic variation in frequency and dividing the beam into a probe beam and a pump beam. The probe beam is directed toward the object, such that the frequency profile of the probe beam after reflection from the object is determined by the depth profile of the object. The pump beam and the reflected probe beam are directed into a nonlinear medium, such that two-wave mixing between the beams occurs in the medium, the two-wave mixing process causing the frequency profile of the probe beam to be converted to an intensity profile. The method may be further refined by adjusting the optical path length of the pump beam in order to adjust the accuracy range of the depth profile which is imaged. In addition, the reflected intensity profile of the object can be obtained from the reflected probe beam prior to the mixing of the probe beam and the pump beam and subtracted from the converted intensity profile to correct the converted intensity profile for variations in the surface reflectivity of the object. A nonlinear optical ranging imager for imaging a three-dimensional object includes a source of coherent light with a periodic variation in frequency and a beam splitter for dividing the source into a pump beam and a probe beam directed at the object, such that a frequency profile of the probe beam after reflection from the object is determined by the depth profile of the object. A nonlinear optical medium receives the reflected probe beam and the pump beam, such that two-wave mixing between the two beams occurs within the medium, the two-wave mixing process causing the frequency profile of the probe beam to be converted to an intensity profile.
A radar system which is used for determining optical range includes a frequency analyzer for the analysis of differential frequency signals, which originate from a mixture of the transmitted signal with the received signals, for example reflected from a fog bank. The frequency spectrum images the distance profile of the fog bank.
A 2D/3D optically controlled spatial and angular electromagnetic wave modulator is disclosed. The modulator of the present invention modulates the amplitude and direction of an electromagnetic wave such as millimeter microwaves or infrared waves by diffracting or scattering the electromagnetic wave from a semiconductor material upon which is incident a controlling lightwave. The lightwave incident upon the semiconductor is of varying intensity, and may be time varying, and changes the complex refractive permittivity of the semiconductor material. The electromagnetic wave is thus modulated in accordance with the controlling lightwave.
Optical communication systems, optical computing systems and optical logic elements which rely on the phenomina of cross-phase modulation to alter and control, either or simultaneously, the spectral, temporal or/and spatial properties of ultrashort light pulses for processing information with high speed repetition rates. A weak beam of ultrashort light pulses is modulated by an intense beam of ultrashort light pulses by copropagating both beams through a non-linear medium such that cross-phase modulation effects are realized.
Optical communication systems, optical computing systems and optical logic elements which rely on the phenomina of cross-phase modulation to alter and control, either or simultaneously, the spectral, temporal or/and spatial properties of ultrashort light pulses for processing information with high speed repetition rates. A weak beam of ultrashort light pulses is modulated by an intense beam of ultrashort light pulses by copropagating both beams through a non-linear medium such that cross-phase modulation effects are realized.
The invention is directed to non-invasive methods and apparatus for three-dimensional measurement of surface profile and/or volume, and analysis of surface texture for evaluation of wound repair, assessment of surgical reconstructions or treatment of hypertrophic scarring, evaluation of polymerization reactions for polymer and elastomeric curing processes, or in any industrial process requiring quantitative monitoring of surface texture and profile. Both volume and surface texture are quantitatively measured very accurately, and the apparatus and method can be used on both soft and hard surfaces according to the above objectives. The invention generally comprises an apparatus and method to image a three-dimensional surface for volumetric analysis and/or surface texture. The apparatus includes a laser source for emitting a predetermined wavelength beam which is reflected off the surface being imaged, and a laser detector or sensor positioned relative to the laser source for receiving the reflected beam to generate a first signal corresponding to the amount of laser energy reflected off the surface. The reflected beam is indicative of changes in the depth of the surface relative to the laser source, and can therefore be used to monitor changes in surface depth. Further, a sound source is provided for generating a coherent beam of sound waves which are reflected off the surface also. A sound detector positioned relative to the sound source receives reflected sound waves to generate at least a second signal corresponding to the amount of sound waves reflected off the surface, wherein the reflected sound waves are a measure of the surface texture. A control system selectively operates the laser source and sound source for generating the signals at a plurality of locations on the surface for analysis. The apparatus may be portable, and provides a quick and accurate quantitative measurement of a surface, and can be used in association with both hard and soft surfaces.
