We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunabl... more We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunable first-order Fabry-Perot Scanning Spectrometer (FPSS). The FPSS operates over 8 – 12 mm with a spectral resolution of 1 % of the wavelength. The FPSS has a 22 degree field of view and a spatial resolution of 0.11 degrees. The key components of the FPSS system are the collection optics, a tunable Fabry-Perot etalon, optical position sensors, a closed-loop positioning system, an uncooled microbolometer focal plane array, a digital frame grabber card, and a user-friendly Graphical User Interface (GUI).
Abstract : The primary objective of this program is to develop a laser warning sensor for the mea... more Abstract : The primary objective of this program is to develop a laser warning sensor for the measurement of laser illumination events during flight at a consumer cost of less than $500. The target requirements are to measure the wavelength, average power, pulse length, pulse repetition frequency, and duration for each event and save the information in a time-stamped downloadable file. The Phase I effort established the feasibility of the proposed approach by performing a detailed analysis of the design, procuring and fabricating a breadboard prototype, and then performing laboratory testing that soundly verified the ability of the sensor to achieve the target requirements. The sensor has excellent commercial potential in all sectors of the Department of Defense as a laser warning sensor, as well as private sector applications in video surveillance and pattern recognition.
The proliferation of lasers has led to their widespread use in applications ranging from short ra... more The proliferation of lasers has led to their widespread use in applications ranging from short range standoff chemical detection to long range Lidar sensing and target designation operating across the UV to LWIR spectrum. Recent advances in high energy lasers have renewed the development of laser weapons systems. The ability to measure and assess laser source information is important to both identify a potential threat as well as determine safety and nominal hazard zone (NHZ). Laser detection sensors are required that provide high dynamic range, wide spectral coverage, pulsed and continuous wave detection, and large field of view. OPTRA, Inc. and Tufts have developed a custom ROIC smart pixel imaging sensor architecture and wavelength encoding optics for measurement of source wavelength, pulse length, pulse repetition frequency (PRF), irradiance, and angle of arrival. The smart architecture provides dual linear and logarithmic operating modes to provide 8+ orders of signal dynamic range and nanosecond pulse measurement capability that can be hybridized with the appropriate detector array to provide UV through LWIR laser sensing. Recent advances in sputtering techniques provide the capability for post-processing CMOS dies from the foundry and patterning PbS and PbSe photoconductors directly on the chip to create a single monolithic sensor array architecture for measuring sources operating from 0.26 – 5.0 microns, 1 mW/cm2 – 2 kW/cm2.
Novel Optical Systems Design and Optimization XVIII, 2015
OPTRA is currently developing a Risley Prism Universal Pointing System (RPUPS): a highly customiz... more OPTRA is currently developing a Risley Prism Universal Pointing System (RPUPS): a highly customizable cued beamsteering system. The RPUPS consists of a visible or infrared cueing imager co-aligned with an optical beam steering system’s pointing-field-of-regard. The cueing imager is used to identify a region-of-interest within its wide field-of-view, via a wireless tablet device. The tablet user can choose to manually or automatically, identify and track regions-of-interest. The optical beam steering system uses a matched pair of Risley Prisms to direct an interrogating optical system’s instantaneous-field-of-view onto the identified region-of-interest. The tablet updates the user with real time information from both the cueing imager and the interrogating optical system. Risley prism material and geometry choices provide operating wavelength, aperture size, and field-of-regard flexibility for this front-end pointing component. Back-end components may be receive-only, transmit-only, or transmit/receive combinations. The flexibility of the RPUPS allows for mission specific customization where applications include but are not limited to: synthetic foveated imaging, spectroscopic probes and laser (LIDAR) ranging and tracking. This paper will focus on the design and anticipated applications of the RPUPS.
The authors present a study focused on the feasibility of using holographic polymer dispersed liq... more The authors present a study focused on the feasibility of using holographic polymer dispersed liquid crystal wavelength filters for hyperspectral imaging (HSI). For this study, stacks of these filters were fabricated in the visible wavelength range of 600 to 800 nm. These filters were demonstrated to have a number of properties useful for HSI applications, including uniform reflection efficiency of 80% across a 35 mm optical aperture, polarization insensitivity for normal incidence, spectral resolution of 10 nm, and fast switching times on the order of microseconds. In addition, the ability to modulate each filter in the stack at a different frequency allows for spectral multiplexing, thus enabling synchronous detection and demodulation of the image data. Although the filters in their current state show promise for HSI applications, techniques to further improve performance in terms of viewing angle range and transmission throughput are presented. Finally, a system level integration of such a stack into the prototype drive and detection unit is discussed.
The primary objective of this effort is to develop a low-cost, self-powered, and compact laser ev... more The primary objective of this effort is to develop a low-cost, self-powered, and compact laser event recorder and warning sensor for the measurement of laser events. The target requirements are to measure the wavelength, irradiance, pulse length, pulse repetition frequency, duration and scenery image for each event and save the information in a time and location stamped downloadable file. The
We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunabl... more We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunable first-order Fabry-Perot Scanning Spectrometer (FPSS). The FPSS operates over 8 O 12 micrometers with a spectral resolution of 1% of the wavelength. The FPSS has a 22 degree field of view and a spatial resolution of 0.11 degrees. The key components of the FPSS system are the collection optics, a tunable Fabry-Perot etalon, optical position sensors, a closed-loop positioning system, an uncooled microbolometer focal plane array, a digital frame grabber card, and a user-friendly Graphical User Interface (GUI).
We present the design of a highly stable, compact system that achieves the frequency stabilizatio... more We present the design of a highly stable, compact system that achieves the frequency stabilization of a distributed feedback laser diode to an excited-state argon transition at 1.323 μm. The argon atomic reference is generated in a miniature hollow cathode lamp. A small a/c magnetic field is used to Zeeman split the transition and both right- and left-circularly polarized light are used to generate the error discriminant signal and cancel laser relative intensity noise. The output does not contain any frequency modulated components and has been measured to have long-term frequency stability of better than 8×10−11 (20 kHz) with the Allan Variance technique.
A new model is described that combines the interaction between two physical mechanisms responsibl... more A new model is described that combines the interaction between two physical mechanisms responsible for bulk third-order optical nonlinearity. They are: (1) saturable absorption, due to quantum confinement in nanoparticles, and (2) electrostriction, causing particles to migrate in the fluid host. We show that enhanced nonlinearities are predicted resulting from local field coupling and that oscillations can occur under certain conditions.
The primary objective of this effort is to develop a low-cost, self-powered, and compact laser ev... more The primary objective of this effort is to develop a low-cost, self-powered, and compact laser event recorder and warning sensor for the measurement of laser events. Previously we reported on the technology and design of the Laser Event Recorder. In this paper we describe results from a series of ground and airborne tests of the Laser Event Recorder.
[Proceedings of SPIE 8018, 80181O (2011)]. Elizabeth Schundler, David Carlson, Robert Vaillancour... more [Proceedings of SPIE 8018, 80181O (2011)]. Elizabeth Schundler, David Carlson, Robert Vaillancourt, Julia Rentz Dupuis, Craig Schwarze. Abstract. ... The Risley scanner is a mature technology, which uses a pair of matched prisms to steer a laser beam anywhere inside a cone. ...
Lasers for defense applications continue to grow in power and fill in new portions of the spectru... more Lasers for defense applications continue to grow in power and fill in new portions of the spectrum, expanding the laser eye safety hazard, particularly to aircrew and aviation safety. The Laser Event Recorder Program within Naval Air Systems Command (NAVAIR) seeks to ...
OPTRA has recently developed Risley-Prism based solutions for compact laser beam steering applica... more OPTRA has recently developed Risley-Prism based solutions for compact laser beam steering applications. Risley prism beam steering systems are smaller, use less power, and weigh less than conventional gimbal-based beam steering systems, which makes them more immune to vibration and able to achieve higher response times and beam steering rates. OPTRA has developed a system for IRCM applications that achieves better than 1 milliradian beam pointing accuracy across 2-4.7 microns over a 110 degree field of regard. The full field response time is 110 milliseconds with peak steering rates greater than 850 degrees per second. The beam steerer is housed in a package 3.2 inches in diameter and 3.5 inches in length, weighs 3.5 lbs, and draws 28 W peak power. OPTRA has also developed a 4 inch aperture beam steering system for free space optical laser communications that operates in the telecom band at 1550 nm. We present a summary of the design and results from testing.
We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunabl... more We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunable first-order Fabry-Perot Scanning Spectrometer (FPSS). The FPSS operates over 8 – 12 mm with a spectral resolution of 1 % of the wavelength. The FPSS has a 22 degree field of view and a spatial resolution of 0.11 degrees. The key components of the FPSS system are the collection optics, a tunable Fabry-Perot etalon, optical position sensors, a closed-loop positioning system, an uncooled microbolometer focal plane array, a digital frame grabber card, and a user-friendly Graphical User Interface (GUI).
Abstract : The primary objective of this program is to develop a laser warning sensor for the mea... more Abstract : The primary objective of this program is to develop a laser warning sensor for the measurement of laser illumination events during flight at a consumer cost of less than $500. The target requirements are to measure the wavelength, average power, pulse length, pulse repetition frequency, and duration for each event and save the information in a time-stamped downloadable file. The Phase I effort established the feasibility of the proposed approach by performing a detailed analysis of the design, procuring and fabricating a breadboard prototype, and then performing laboratory testing that soundly verified the ability of the sensor to achieve the target requirements. The sensor has excellent commercial potential in all sectors of the Department of Defense as a laser warning sensor, as well as private sector applications in video surveillance and pattern recognition.
The proliferation of lasers has led to their widespread use in applications ranging from short ra... more The proliferation of lasers has led to their widespread use in applications ranging from short range standoff chemical detection to long range Lidar sensing and target designation operating across the UV to LWIR spectrum. Recent advances in high energy lasers have renewed the development of laser weapons systems. The ability to measure and assess laser source information is important to both identify a potential threat as well as determine safety and nominal hazard zone (NHZ). Laser detection sensors are required that provide high dynamic range, wide spectral coverage, pulsed and continuous wave detection, and large field of view. OPTRA, Inc. and Tufts have developed a custom ROIC smart pixel imaging sensor architecture and wavelength encoding optics for measurement of source wavelength, pulse length, pulse repetition frequency (PRF), irradiance, and angle of arrival. The smart architecture provides dual linear and logarithmic operating modes to provide 8+ orders of signal dynamic range and nanosecond pulse measurement capability that can be hybridized with the appropriate detector array to provide UV through LWIR laser sensing. Recent advances in sputtering techniques provide the capability for post-processing CMOS dies from the foundry and patterning PbS and PbSe photoconductors directly on the chip to create a single monolithic sensor array architecture for measuring sources operating from 0.26 – 5.0 microns, 1 mW/cm2 – 2 kW/cm2.
Novel Optical Systems Design and Optimization XVIII, 2015
OPTRA is currently developing a Risley Prism Universal Pointing System (RPUPS): a highly customiz... more OPTRA is currently developing a Risley Prism Universal Pointing System (RPUPS): a highly customizable cued beamsteering system. The RPUPS consists of a visible or infrared cueing imager co-aligned with an optical beam steering system’s pointing-field-of-regard. The cueing imager is used to identify a region-of-interest within its wide field-of-view, via a wireless tablet device. The tablet user can choose to manually or automatically, identify and track regions-of-interest. The optical beam steering system uses a matched pair of Risley Prisms to direct an interrogating optical system’s instantaneous-field-of-view onto the identified region-of-interest. The tablet updates the user with real time information from both the cueing imager and the interrogating optical system. Risley prism material and geometry choices provide operating wavelength, aperture size, and field-of-regard flexibility for this front-end pointing component. Back-end components may be receive-only, transmit-only, or transmit/receive combinations. The flexibility of the RPUPS allows for mission specific customization where applications include but are not limited to: synthetic foveated imaging, spectroscopic probes and laser (LIDAR) ranging and tracking. This paper will focus on the design and anticipated applications of the RPUPS.
The authors present a study focused on the feasibility of using holographic polymer dispersed liq... more The authors present a study focused on the feasibility of using holographic polymer dispersed liquid crystal wavelength filters for hyperspectral imaging (HSI). For this study, stacks of these filters were fabricated in the visible wavelength range of 600 to 800 nm. These filters were demonstrated to have a number of properties useful for HSI applications, including uniform reflection efficiency of 80% across a 35 mm optical aperture, polarization insensitivity for normal incidence, spectral resolution of 10 nm, and fast switching times on the order of microseconds. In addition, the ability to modulate each filter in the stack at a different frequency allows for spectral multiplexing, thus enabling synchronous detection and demodulation of the image data. Although the filters in their current state show promise for HSI applications, techniques to further improve performance in terms of viewing angle range and transmission throughput are presented. Finally, a system level integration of such a stack into the prototype drive and detection unit is discussed.
The primary objective of this effort is to develop a low-cost, self-powered, and compact laser ev... more The primary objective of this effort is to develop a low-cost, self-powered, and compact laser event recorder and warning sensor for the measurement of laser events. The target requirements are to measure the wavelength, irradiance, pulse length, pulse repetition frequency, duration and scenery image for each event and save the information in a time and location stamped downloadable file. The
We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunabl... more We present a new hyperspectral imaging system for the long wave infrared (LWIR) based on a tunable first-order Fabry-Perot Scanning Spectrometer (FPSS). The FPSS operates over 8 O 12 micrometers with a spectral resolution of 1% of the wavelength. The FPSS has a 22 degree field of view and a spatial resolution of 0.11 degrees. The key components of the FPSS system are the collection optics, a tunable Fabry-Perot etalon, optical position sensors, a closed-loop positioning system, an uncooled microbolometer focal plane array, a digital frame grabber card, and a user-friendly Graphical User Interface (GUI).
We present the design of a highly stable, compact system that achieves the frequency stabilizatio... more We present the design of a highly stable, compact system that achieves the frequency stabilization of a distributed feedback laser diode to an excited-state argon transition at 1.323 μm. The argon atomic reference is generated in a miniature hollow cathode lamp. A small a/c magnetic field is used to Zeeman split the transition and both right- and left-circularly polarized light are used to generate the error discriminant signal and cancel laser relative intensity noise. The output does not contain any frequency modulated components and has been measured to have long-term frequency stability of better than 8×10−11 (20 kHz) with the Allan Variance technique.
A new model is described that combines the interaction between two physical mechanisms responsibl... more A new model is described that combines the interaction between two physical mechanisms responsible for bulk third-order optical nonlinearity. They are: (1) saturable absorption, due to quantum confinement in nanoparticles, and (2) electrostriction, causing particles to migrate in the fluid host. We show that enhanced nonlinearities are predicted resulting from local field coupling and that oscillations can occur under certain conditions.
The primary objective of this effort is to develop a low-cost, self-powered, and compact laser ev... more The primary objective of this effort is to develop a low-cost, self-powered, and compact laser event recorder and warning sensor for the measurement of laser events. Previously we reported on the technology and design of the Laser Event Recorder. In this paper we describe results from a series of ground and airborne tests of the Laser Event Recorder.
[Proceedings of SPIE 8018, 80181O (2011)]. Elizabeth Schundler, David Carlson, Robert Vaillancour... more [Proceedings of SPIE 8018, 80181O (2011)]. Elizabeth Schundler, David Carlson, Robert Vaillancourt, Julia Rentz Dupuis, Craig Schwarze. Abstract. ... The Risley scanner is a mature technology, which uses a pair of matched prisms to steer a laser beam anywhere inside a cone. ...
Lasers for defense applications continue to grow in power and fill in new portions of the spectru... more Lasers for defense applications continue to grow in power and fill in new portions of the spectrum, expanding the laser eye safety hazard, particularly to aircrew and aviation safety. The Laser Event Recorder Program within Naval Air Systems Command (NAVAIR) seeks to ...
OPTRA has recently developed Risley-Prism based solutions for compact laser beam steering applica... more OPTRA has recently developed Risley-Prism based solutions for compact laser beam steering applications. Risley prism beam steering systems are smaller, use less power, and weigh less than conventional gimbal-based beam steering systems, which makes them more immune to vibration and able to achieve higher response times and beam steering rates. OPTRA has developed a system for IRCM applications that achieves better than 1 milliradian beam pointing accuracy across 2-4.7 microns over a 110 degree field of regard. The full field response time is 110 milliseconds with peak steering rates greater than 850 degrees per second. The beam steerer is housed in a package 3.2 inches in diameter and 3.5 inches in length, weighs 3.5 lbs, and draws 28 W peak power. OPTRA has also developed a 4 inch aperture beam steering system for free space optical laser communications that operates in the telecom band at 1550 nm. We present a summary of the design and results from testing.
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