Pyrocam IV images laser beams to terahertz range

Posted by Gail Overton
http://www.laserfocusworld.com/articles/2014/08/pyrocam-iv-images-laser-beams-to-terahertz-range.html

Ophir-Spiricon's pyroelectric or thermal-electric Pyrocam cameras have allowed laser users working with ultraviolet (UV), infrared (IR), and terahertz (THz) wavelengths to image and characterize laser sources for more than 30 years. But the new, fourth-generation Pyrocam IV (see video at http://bcove.me/iq5gsjqt) adds greater sensitivity, better resolution, a larger active area, and more compact packaging to address next-generation laser source requirements.

RELATED ARTICLE: How to select a beam-profile measurement system

Better sensitivity of the Pyrocam IV's imager allows profiling of lasers with lower power density levels than the Pyrocam III. While the Pyrocam III specified a sensitivity level of 2.2 mW/cm² at a 24 Hz chop rate, the Pyrocam IV specifies 1.0 mW/cm² at its equivalent chop rate. Pyrocam IV also has a 36% higher saturation level of 3.0 W/cm² compared to the Pyrocam III's 2.2 W/cm² (at equivalent chop rates), giving the Pyrocam IV the greatest range of usable power densities to date.  Military labs and those working with low-level THz sources (usually working in tens of microwatts to single-digit milliwatt ranges) benefit from this increased sensitivity. Recently, one of the Naval Research Lab’s laser scientists was thrilled to be able to see his terahertz beam for the very first time.

The 20% smaller pixel pitch from the Pyrocam III's 100 µm to the Pyrocam IV's 80 µm pitch enables more flexibility, both in beam sizes being profiled and the amount of data being collected. DoE and DoD research facilities and others working with relatively small beams have commented that they are now able to collect more reliable data with more pixels illuminated. Used in conjunction with Spiricon's newly-released LBS-400 beam attenuation system, laser users can accurately image focused spots up to 500 W of average power and down to about 1.5 mm in diameter. This allows for the characterization of high-powered industrial lasers being used in manufacturing environments.

The Pyrocam IV uses an active area of 25.6 mm square that is more than twice that of the Pyrocam III’s 12.4 mm square active area. Couple this with the smaller pixels and the result is Pyrocam IV's 320 x 320 resolution compared to Pyrocam III's 124 x 124 resolution. Recently, a fiber manufacturer purchased a Pyrocam IV on the spot after experiencing the beam divergence measurements from his highly-divergent light. The large active area allowed them to take measurements that ultimately led to qualification of their products that they had not previously been able to accomplish.

Technological advancements have allowed for more compact packaging in the Pyrocam IV. While the predecessor Pyrocam III has a thickness of just over 3 inches, the Pyrocam IV is 2.18 inches thick. And while the overall width and height dimensions are similar between the two cameras, the Pyrocam IV has progressed past a rectangular shape to allow the laser user more flexibility in its placement. The Pyrocam IV case also has different interfaces, such as an SMA connection instead of a BNC connection for triggering the camera to allow for more efficient cable management.

Because Ophir-Spiricon realizes that the new case design could cause problems for customers who would like to use the new Pyrocam IV but have system designs around the Pyrocam III form factor, the company is introducing the Pyrocam III-HR which has the new Pyrocam features packaged in the Pyrocam III case.

Some additional Pyrocam IV upgrades are that Ophir-Spiricon has moved away from the legacy FireWire interface to a Gigabit Ethernet interface. Also, in conjunction with the introduction of the Pyrocam IV, the company's BeamGage beam analysis software has also gone through some updates. The most recent release of v6.3 (a free upgrade to those using BeamGage v5.0 or later), allows for a more user-friendly interface to the Pyrocam camera, as well as several front-end and back-end software enhancements.

For more detailed information on Pyrocam IV, please contact Ophir-Spiricon product specialist John McCauley at John.mccauley@us.ophiropt.com.

IMAGE: The Pyrocam IV thermal-electric camera can image and characterize laser beams with high resolution over a broad range of emission frequencies. (Image credit: Ophir-Spiricon)

SOURCE: Ophir-Spiricon; http://www.laserfocusworld.com/articles/2014/04/ophir-photonics-to-showcase-pyroelectric-camera-for-2d-3d-laser-diagnostics-at-spie-dss-2014.html

Ophir Photonics Announce Pyroelectric Laser Beam Profiling Camera Pyrocam IVs

Ophir Photonics, global leader in precision laser measurement equipment and a Newport Corporation brand, today announced the PyrocamTM; IVs, the newest member of the PyrocamTM family of pyroelectric laser beam profiling cameras.

http://www.azooptics.com/News.aspx?newsID=19503

The Pyrocam IVs is the next generation of the popular Pyrocam III. It features a more sensitive, 160 x 160 pixel image array that can profile beams up to ½-inch (12.8 mm) without the need for reduction optics. The Pyrocam IVs measures both pulsed and CW (continuous wave) lasers, from 13 to 355 nm and 1.06 to >3000 µm. An integral focal plane chopper is included for CW beams and thermal imaging.

"The Pyrocam cameras are the only way to see 3D views of long wavelength lasers, CO2and beyond," said Gary Wagner, General Manager (U.S.), Ophir Photonics. "The increased sensitivity and longer wavelength range of the Pyrocam IVs make it ideal for the burgeoning terahertz lasers market. Terahertz laser power is increasing in leaps and bounds for a wide range of applications, from chemical analysis and security scanning to medical imaging and telecommunications."

The Pyrocam IVs allows you to see the beam for dynamic alignment and proper operation of CO2 and telecom NIR lasers, as well as other infrared sources out to the Far IR THz range. For high-speed applications, it includes an interface to GigE (Gigabit Ethernet) cameras. A 14-bit A/D converter provides reliable measurement and analysis of both large signals and low level signals in the wings of the laser beam. A signal to noise ratio of 1000:1 means beams of 30 mW/cm2 are easily visible.

The Pyrocam IVs ships with BeamGage®, the company's advanced laser beam analysis software. This provides 2D and 3D viewing of beams and includes the algorithms and calculations needed to make accurate, ISO approved, NIST-traceable beam measurements. Measurements include total and peak power/energy, peak and centroid location, beam diameter, and X/Y knife edge beam widths. The patented Ultracal® baseline algorithm in BeamGage® eliminates background noise, ensuring the highest degree of measurement accuracy.

Ophir-PyrocamTM III Series

 

http://www.ophiropt.com/laser-measurement-instruments/beam-profilers/products/industrial-applications/the-cameras/pyrocam

Pyroelectric Array Camera

PyrocamTM III Series Spectral ranges available from 13 to 355 nm and 1.06 to >3000 µm Image CO2 lasers, telecom NIR lasers and other infrared sources out to Far IR THz sources Solid state array camera with 1000:1 linear dynamic range for accurate profiling Integrated chopper for CW beams and thermal imaging Versatile Firewire interface Interchangeable windows available for a variety of applications Image Viewer utility presents 3D isometric plots, 2D color contour plots and grayscale, among other views Includes BeamGage Laser Beam Analysis Software for extensive quantitative analysis and image display

Description

Specifications

Ordering Info

Catalog/Manual

Download Data Sheet.

Spiricon has been the world leader in the manufacture of pyroelectric solidstate detector arrays and cameras. For over 25 years the Pyrocam™ has been the overwhelming camera of choice for Laser Beam Diagnostics of IR and UV lasers and high temperature thermal imaging. Precision, stability, reliability, and versatility have become its proud heritage. The Pyrocam™ III offers easy Windows ® camera setup, direct Windows quantitative and image display, 14 bit digitizer, versatile Firewire® PC interface, an integral chopper for CW beams and thermal imaging, and many other enhanced features. See Your Beam As Never Before The Pyrocam™ III camera creates clear and illuminating images of your laser beam profile. Displayed in 2D or 3D views, you can immediately recognize beam characteristics that affect laser performance and operation. This instantly alerts you to detrimental laser variations. Instantaneous feedback enables timely correction and real-time tuning of laser parameters including laser alignment. For example, when an industrial shop foreman saw the CO2 laser beam profile in Figure 1 he knew immediately why that laser was not processing materials the same as the other shop lasers, with the profile shown in Figure 2. Fig. 1. Industrial CO2 laser performing inconsistent processing. Fig. 2. Industrial CO2 laser performing specifed processing.

Pulsed and CW Lasers The Pyrocam™ III measures the beam profile of both pulsed and CW lasers. Since the pyroelectric crystal is an integrating sensor, pulses from femtosecond to 12.8ms can be measured. The pyroelectric crystal only measures changes in intensity, and so is relatively immune to ambient temperature changes. Because CW laser beams must be chopped to create a changing signal, the Pyrocam™ III contains an integral chopper as an option. Measuring Terahertz Beam Profiles Spiricon’s Pyrocam™ III pyroelectric camera is an excellent tool for measuring THz lasers and sources. The coating of the crystal absorbs all wavelengths including 1um to over 3000um (0.1THz to 300THz). For THz sources the sensitivity of the Pyrocam™ III is relatively low, at about 300mW/cm2 at full output. With a S/N of 1000, beams of 30mW/cm2 are easily visible. In addition, with Spiricon’s patented Ultracal baseline setting, multiple frames can be summed to “pull” a signal out of the noise. Summing 256 frames enables viewing of beams as low as 1-2mW/cm2. With Terahertz research suddenly being a central topic of interest, the Pyrocam™ III becomes an invaluable aid in this exciting research. Otherwise, scientists working on Terahertz research had no easy way to characterize the profile, or energy distribution, of their lasers or sources. Broad Wavelength Response THz laser beam at 0.2THz (1.55mm) 3mW input power; 19 frames summed. The Pyrocam™ III detector array has a very broadband coating which enables operation at essentially all IR and UV laser wavelengths. The curve ends at 100nm in the UV, but X-ray operation has been observed. Likewise the curve ends at 100μm in the far IR, but the camera has been used at >3000μm. Thus you can use the Pyrocam™ III in the near IR for Nd:YAG lasers at 1.06μm, and for infrared fiber optics at 1.3μm and 1.55μm. Use the Pyrocam™ III for HF/DF lasers near 4μm and for Optical Parametric Oscillators from 1 μm to 10μm. It measures Free Electron Lasers between 10μm and 3000μm. The Pyrocam™ III is extremely useful in the UV from 355nm to 157nm for Excimer lasers and for tripled or quadrupled Nd:YAG lasers. The detector is stable under UV illumination, without the deterioration experienced by CCD cameras. (The pyroelectric detector operates in the visible spectrum, and can see the alignment HeNe used with CO2 lasers. However, spurious response from the underlying silicon multiplexer creates undesirable performance, and the camera is not recommended for quantitative visible measurements). Fig. 6. Spectral response of Pyrocam™ III detector array (without window). Er:YAG laser at 2.9µm. Output of infrared fiber optic. THz laser beam at 1.6THz (184um). Free Electron laser at 100µm.

Windows® PC Interface The Pyrocam™ III Windows application incorporates setup software to control all functions of the camera, such as pulsed versus chopped operation, gain, and background reference subtraction, eliminating all controls from the camera housing. Pyrocam III Windows setup menu.   Windows Image Viewer A Windows viewer application enables viewing of the laser beam in a number of modes, including 3D isometric plots, 2D color contour plots, and gray scale for thermal imaging. This application enables stand-alone operation of the camera independent of any other software. Nevertheless, the Spiricon LBA-PC beam analysis software provides many additional features and capabilities not incorporated with the camera.   Composite Excimer LASIK beam profile at 193nm. Composite Excimer LASIK beam profile in 2D display.   Hybrid Integrated Circuit Sensor The Pyrocam™ III consists of a LiTa03 pyroelectric crystal mounted with indium bumps to a solid-state readout multiplexer. This sensor, developed for the Pyrocam I, has proven to be the most rugged, stable, and precise IR detector array available. Light impinging on the pyroelectric crystal is absorbed and converted to heat, which creates charge on the surface. The multiplexer then reads out this charge onto the video line. For use with short laser pulses, the firmware of the camera creates a very short electronic shutter to accurately capture the thermally generated signal. Pyrocam III sensor array and window assembly

State-Of-The-Art Electronics The camera features a 14 bit A/D converter which digitizes deep into the camera noise. This enables reliable measurement and analysis of both large signals and low level signals in the wings of the laser beam. Fourteen bit digitizing also enables accurate signal summing and averaging to pull weak signals out of noise. This is especially useful with fiber optics at 1.3μm and 1.55μm, and in thermal imaging. The Pyrocam™ III camera electronics incorporates 2 Firewire® (IEEE 1394A) interface ports. Multiple Pyrocam IIIs can be daisy chained together using the 1394 cabling. New Housing & Chopper The Pyrocam™ III incorporates a new compact housing measuring only 5.5” high by 5.1” wide, and 2.5” deep in the direction of the beam path. This allows the camera to be inserted into smaller spaces on the optical table. It also makes the camera useful as a portable camera for thermal imaging and on-site field service of laser systems. The Pyrocam III integral focal plane chopper helps keep the camera head compact. Applications Of The Pyrocam III The Pyrocam™ III is an ideal camera for use in scientific laboratory investigation of laser beams. This includes physics, chemistry, and electronic system designs. As an example, the photos below show a research CO2 laser and a research Nd:YAG laser, both with cavity misalignment. The camera is also useful in product engineering of CO2 and other infrared lasers. The Pyrocam™ III is an integral part of the assembly lines of many CO2 laser manufacturers. Integrators of systems are using the Pyrocam™ sensor to make sure that optical systems are aligned and operating properly. There are many medical applications of the Pyrocam™ III, such as the analysis of excimer lasers used for eye surgery. In many cases these lasers need alignment to ensure that the eye surgery is performed as expected. Other medical IR lasers perform dermatology, for which the uniformity of the beam profile must be assured. Fiber optic communications, at 1.3μm and 1.55μm make significant use of the Pyrocam™ III for analyzing the beams being emitted, as well as analyzing properties of the beams before launching them into fibers. The greater stability of the Pyrocam™ III make it a good choice over other cameras operating at telecommunication wavelengths.   CO2 laser with cavity misalignment. Nd:YAG laser with cavity misalignment.   CO2 laser with cavity misalignment. Nd:YAG laser with cavity misalignment.

The Pyrocam™ III is becoming an essential tool in the maintenance of industrial infrared lasers, especially CO2. The Pyrocam™ III replaces non-electronic mode burns and acrylic blocks by providing higher definition electronic recording of data, and analysis of short term fluctuations. The Pyrocam™ III is superior to other electronic methods of measuring CO2 lasers in that the entire beam can be measured in a single pulse, and additional measurements made in real-time. This ensures that the beam did not change during the measurement.   Detector Damage Threshold The Pyrocam™ III sensor is capable of operation with intensities about 106 greater than CCD cameras. This makes the camera ideal for use with high power lasers, as less attenuation is required. Nevertheless, pulsed lasers with fluence too high can evaporate the absorbing front electrode. As shown the damage threshold increases with pulse width. With nanosecond and longer pulses, detector saturation occurs before damage. With shorter pulses it helps to increase the camera amplifier gain so that electronic saturation occurs before damage. The sensor can be damaged by excessive CW power, which causes crystal cracking. Very few Pyrocam III detectors have been damaged by CW power, but some have been ablated by high peak pulse energy.

 

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Ophir-Spiricon opens clean room for production of solid-state pyroelectric detector arrays

http://www.optoiq.com/index/photonics-technologies-applications/lfw-display/lfw-article-display/5302578148/articles/optoiq2/photonics-technologies/news/business-news/2011/7/ophir-spiricon-opens.html

Logan, UT--Ophir-Spiricon has opened a clean room at its new facility. The 840-sq-ft clean room is used for manufacturing the solid-state pyroelectric detector arrays used in the company's Pyrocam beam-profiling cameras.

The new clean room houses photolithography and thin-film-deposition processes. As is standard in photolithographic clean rooms, yellow lighting is used to prevent premature exposure of the photolithography materials used. The clean room complies with ISO 7 standards for airflow and filtration.

"The new clean room provides a cleaner production environment," stated Gary Wagner, president of Ophir-Spiricon. "This translates into less defects and better yield for both the

lithography and thin-film-deposition processes. In addition, we can produce larger, more dense arrays with higher pixel-fill factors for higher-resolution cameras."

Pyrocam is a solid-state, pyroelectric camera designed to create images of laser beam profiles. It measures the beam profile of both pulsed and continuous-wave lasers, for spectral ranges from 13 to 355 nm and 1.06 to 3000 µm. This includes deep-UV, excimer lasers, CO₂ lasers, telecom near-IR lasers, and far-IR sources to the terahertz regon.

For more info, see http://bit.ly/l9poHF