Wisconsin Alumni Research Foundation

Scott Thomas Sanders

Thilo Kraetschmer

Joachim Walewski

Joseph Andrews

Mario Trujillo

Joachim Werner Walewski

An aerosol jet printer producing a stream of droplets in a print jet employs direct, droplet-resolving imaging to characterize the statistics of the droplets in flight for improved control of the printed line characteristics.

Aerosol jet printer providing in-flight aerosol characterization

An optical sensor for sensing combustion products avoids fouling and damage to optical components by using a 'windowless' design in which an air curtain through an orifice provides a constantly refreshing transparent shield protecting the optical components from corrosive combustion gases and resisting the accumulation of particulates that might otherwise foul a static window.

Combustion gas sensor assembly for engine control

A remote sensor element for spectrographic measurements employs a monolithic assembly of one or two fiber optics to two optical elements separated by a supporting structure to allow the flow of gases or particulates therebetween. In a preferred embodiment, the sensor element components are fused ceramic to resist high temperatures and failure from large temperature changes.

Monolithic fiber optic sensor assembly

An absorption spectrometer provides improved rejection of background radiation signal by employing a frequency-swept laser signal without frequency dithering and performing an effective differentiation of output light from a test cell to eliminate these constant or slowly varying background radiation levels.

Background-free absorption spectroscopy using spectral differentiator

A multi-spectral laser system produces first and second output frequencies by nonlinear mixing of a first, second, and third laser light frequency in a single periodically polled crystal, where the first and second output frequencies are separated by a range greater than the degeneracy of the crystal.

Multi-spectral laser source employing periodically poled crystal mixer

A high-speed absorption spectrographic system employs a slit-less spectroscope to obtain high-resolution, high-speed spectrographic data of combustion gases in an internal combustion engine allowing precise measurement of gas parameters including temperature and species concentration.

High-speed spectrographic sensor for internal combustion engines

A laser provides a cavity with complementary wavelength-dependent delay elements to provide the same optical length but time-staggered light paths for different colors. This provides the ability to individually control multiple narrow bands of colors each in a separate time division window.

Multispectral laser with improved time division multiplexing

A mode-locked laser employs a light-wavelength-dependent, path-length adjuster to provide different path-lengths for multiple light frequencies and dual modulation frequencies selecting multiple modes with different wavelengths. The result is a single cavity laser producing mode-locked light outputs at defined different frequencies. Tuning of each frequency may be obtained by changing the laser modulation frequencies.

Multi-wavelength mode locked laser

An apparatus and method are provided for conducting heterodyne frequency-comb spectroscopy. The apparatus includes a first and second frequency-comb generators for generating corresponding first and second continuous wave laser beams, respectively. The first beam defines a spectrum of light having a plurality of modes spaced by a first frequency. The second beam defines a spectrum of light having a plurality of modes spaced by a second frequency that is greater than the first frequency. The first and second beams are combined and the optical power of the combined beam is monitored with a data acquisition system to record a time trace. The recorded time trace is Fourier transformed such that each of spectrums of the first and second beams will exhibit a low-frequency comb. By superimposing the two combs, a beat frequency in a low-frequency region is assigned to an optical frequency.

Method and apparatus for conducting heterodyne frequency-comb spectroscopy

An external cavity laser may be swept rapidly in frequency and cavity length to prevent formation of modes providing improved spectral response and light characteristics.

Modeless wavelength-agile laser

An ultraviolet super-continuum source with a fiber-optic may be provided with direct stimulation by a laser having a relatively narrow bandwidth, for example, less than the typical Raman shift in the material of the optical fiber to provide a super-continuum source extending for wavelengths below 400 nanometers.

Super-continuum UV source

A high scan rate spectroscopic system converts a narrow-band laser pulse into a multispectral pulse, using, for example, a nonlinear fiber. The multispectral pulse is then converted to a swept frequency pulse through a second fiber impressing a frequency-dependent delay in the light beam which is then applied to the object to be tested.

Growing community of inventors

Middleton, WI, United States of America

Scott Thomas Sanders