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Patent
Ondax Inc | Date: 2015-09-21

Systems and methods are provided herein. An exemplary system may include a laser source, the laser source having a laser center wavelength; at least one narrowband optical element receiving light emitted by the laser, the narrowband optical element having a filter center wavelength, the narrowband optical element being arranged such that the filter center wavelength is initially spectrally aligned with the laser center wavelength, the filter center wavelength changing in response to a temperature change such that the filter center wavelength is not substantially aligned with the laser center wavelength; and a passive adjustment mechanism coupled to the narrowband optical element, the passive adjustment mechanism including an actuator, the actuator moving in response to the temperature change, the actuator motion rotating the narrowband optical element, the rotation compensating for the temperature change such that the filter center wavelength and laser center wavelength remain spectrally aligned.


Moser C.,Ondax Inc | Havermeyer F.,Ondax Inc
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

We report low frequency Stokes and anti-Stokes Raman spectra resolving frequency shifts down to 15 cm-1 using a standard commercial Raman spectrometer with ultra-narrow band notch filters. The ultra-narrow band notch filters were fabricated holographically in a glass material with optical densities ranging from 4 to 6 per notch filter at the standard Raman laser lines of 488 nm, 532 nm, 633 nm and 785 nm. The notch filters have greater than 80% transmission at 15cm-1 away from the laser line. This simple notch filter-based system provides high performance low frequency Raman spectroscopy as a low cost alternative to bulky and expensive triple spectrometer Raman systems. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Carriere J.T.A.,Ondax Inc | Havermeyer F.,Ondax Inc | Heyler R.A.,Ondax Inc
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Raman and Terahertz spectroscopy are both widely used for their ability to safely and remotely identify unknown materials. Each approach has its advantages and disadvantages. Traditional Raman spectroscopy typically measures molecular energy transitions in the 200-5000cm-1 region corresponding to sub-molecular stretching or bending transitions, while Terahertz spectroscopy measures molecular energy transitions in the 1-200cm-1 region (30GHz - 6THz) that correspond to low energy rotational modes or vibrational modes of the entire molecule. Many difficult to detect explosives and other hazardous chemicals are known to have multiple relatively strong transitions in this "Terahertz" (<200cm-1, <6THz) regime, suggesting this method as a powerful complementary approach for identification. However, THz signal generation is often expensive, many THz spectroscopy systems are limited to just a few THz range, and strong water absorption bands in this region can act to mask certain transitions if great care isn't taken during sample preparation. Alternatively, low-frequency or "THz-Raman" spectroscopy, which covers the ~5cm-1 to 200cm-1 (150GHz - 6 THz) regions and beyond, offers a powerful, compact and economical alternative to probe these low energy transitions. We present results from a new approach for extending the range of Raman spectroscopy into the Terahertz regime using an ultra-narrow-band volume holographic grating (VHG) based notch filter system. An integrated, compact Raman system is demonstrated utilizing a single stage spectrometer to show both Stokes and anti-Stokes measurements down to <10cm-1 on traditionally difficult to detect explosives, as well as other chemical and biological samples. ©2013 SPIE.


Moser C.,Ondax Inc | Havermeyer F.,Ondax Inc
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

We have developed a novel method to correct the spatial distortion resulting from temporally stretching/compressing optical pulses with a chirped volume holographic grating (CVHG) in glass. We show that the inherent spatial beam distortion can be corrected to produce a distortion-free round beam output. We fabricated a 30 mm long CVHG with 9 nm bandwidth, 300 ps delay at 1031nm exhibiting a smooth round spatial Gaussian profile after compression. Coupling efficiencies for the compressed pulse exceeds 75% into a single mode fiber. The spatial profile is maintained over a wide temperature range from 10 to 60 degrees Celsius. We believe that the spatial beam profile improvements of CVHG demonstrate herein enables the practical realization of ultra-compact and efficient chirped pulse amplification laser systems. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Havermeyer F.,Ondax Inc | Ho L.,Ondax Inc | Moser C.,Ecole Polytechnique Federale de Lausanne
Optics Express | Year: 2011

The wavelength tuning properties of a tunable external cavity laser based on multiplexed volume holographic gratings and a commercial micromirror device are reported. The 3x3x3 cm3 laser exhibits single mode operation in single or multi colors between 776 nm and 783 nm with less than 7.5 MHz linewidth, 37 mW output power, 50 μs rise/fall time constant and a maximum switching rate of 0.66 KHz per wavelength. The unique discrete-wavelength-switching features of this laser are also well suited as a source for continuous wave Terahertz generation and three-dimensional metrology. © 2011 Optical Society of America.


Grant
Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 499.94K | Year: 2010

This Small Business Innovation Research (SBIR) Phase II project focuses on the development, manufacturing and commercialization of a novel miniature self-aligned tunable diode laser. The tunable laser platform offers two major advantages compared to currently available products and technologies: (1) passive optical alignment and assembly; and (2) extremely broad spectral coverage from visible (375nm) to the infrared (4,000nm). The self-alignment feature translates to much simpler and efficient manufacturing, and the optical design enables the new platform to be two orders of magnitude more compact than commercially available tunable diode lasers. These features combine to considerably lower the labor costs associated with assembly and packaging. The research objectives are to determine the parameters of the passive cavity that enable (1) stable single frequency operation, (2) a linewidth less than 30KHz, and (3) less than 1MHz wavelength drift. It is also critical to develop methods to tune the output to a specific target wavelength. Prototypes of the tunable laser will be built for three wavelength groups: blue (400-415 nm) ? Red (635-660 nm) and near-infrared (760-790 nm). This novel laser platform will enable a broad range of technology areas. The broader impact/commercial potential of this project has direct links to commercial applications that decrease energy use or promote renewable energy implementation. Specifically, this laser technology can assist the reduction of carbon emissions by monitoring and optimizing efficiencies in combustion processes such as engines and coal plants (via gas sensing with infrared tunable lasers). The technology will help accelerate the deployment of environmental sensing stations by providing the key optical source for sensing systems at a fraction of today?s cost. A second role would be to provide athermal operation of lasers, which could significantly reduce the energy consumption in telecommunication systems by eliminating the requirement for cooling the lasers. A third application would be improving the efficiency of renewable wind power (via wind sensing with blue-violet lasers) by enabling ?smart? wind turbines. A laser-based wind sensor would provide each ?smart? turbine of a wind farm with the ability to preemptively assess and accurately predict the wind load far in advance, helping improve overall turbine efficiency and utilization. This information is critical to the planning of energy supply into the power grid. All of these applications have immediate commercial potential to help reduce the World?s dependence on fossil fuels.


Patent
Ondax Inc | Date: 2011-05-24

The present invention relates to methods of measuring the optical characteristics of volume holographic gratings with high resolution and with a large spectral coverage using a spectrally broad band source in conjunction with instruments that measure the spectrum such as spectrometers, imaging spectrometers, and spectrum analyzers.


Patent
Ondax Inc | Date: 2011-05-24

The invention disclosed here teaches methods and apparatus for altering the temporal and spatial shape of an optical pulse. The methods correct for the spatial beam deformation caused by the intrinsic DC index gradient in a volume holographic chirped reflective grating (VHCRG). The first set of methods involves a mechanical mean of pre-deforming the VHCRG so that the combination of the deflection caused by the DC index gradient is compensated by the mechanical deformation of the VHCRG. The second set of methods involves compensating the angular deflection caused by the DC index gradient by retracing the diffracted beam back onto itself and by re-diffracting from the same VHCRG. Apparatus for temporally stretching, amplifying and temporally compressing light pulses are disclosed that rely on the methods above.


Trademark
Ondax Inc | Date: 2013-02-27

Spectroscopy instruments and accessories, comprised of specialized optical filters, lasers, detectors, sensors, microscopes and computer software and hardware, used for measuring the chemical composition and molecular structure of materials.

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