Our Technology: Visual and Near IR Illumination
Our Technology: Incoherent, Broadband Optical Radiation
Our StunRay® technology is based on Xenon short-arc lamps, which are the closest possible practical implementation to an ideal point source of light. A Xenon short-arc lamp consists of a spherical or slightly ellipsoidal quartz bulb that is filled with xenon gas, at a high pressure. Two electrodes penetrate into the bulb, and the tips of the electrodes are only a few millimeters apart. During operation, electrical power is applied to the electrodes, and an arc is formed. Given that the arc size is relatively small, and the applied electrical power is relatively large, the arc is very intense.
The lamp converts electrical power into incoherent, broadband optical radiation, with ultra-violet (UV), visible, and near infrared (IR) wavelengths, with a spectrum as shown in Figure 1. The vertical axis is the spectral irradiance, in μW/cm2-nm, and the horizontal axis is the wavelength of the radiation, in nanometers (nm). 11% of the irradiance is ultraviolet, with wavelengths between 200 and 400 nm, 34% of the irradiance is light, with wavelengths between 400 and 700 nm, and 54% of the irradiance is infrared, with wavelengths between 700 and 2500 nm.
Figure 1. Spectral irradiance
The spectrum is nearly uniform for the visible wavelengths, and has some significant near infrared peaks. The radiation has a color temperature of approximately 5800 degrees Kelvin, and is an icy pure white visible light that is only very slightly bluer than noontime tropical sunlight in clean air.
Since shorter wavelengths have higher energy photons, and are generally biologically more effective, the ultra-violet (UV) wavelengths, which not only are a particular acute biological tissue risk, for both the eye and the skin, but are not needed for general night-time illumination, are typically blocked at the source. The UV radiation may, however, be un-blocked for specific applications that do not involve exposure to the eye.
Since the magnitude of the spectral irradiance is approximately constant within the range of visible wavelengths, the visible radiation appears to be white light. The infrared radiation is not visible, and is felt as heat.
Power Conversion & Control
Since Xenon short-arc lamps range in size from 20 watts to more than 10,000 watts, our technology is both modular and scalable, to enable the rapid development of additional multi-function products that are optimized for specific end-uses, where an extremely intense light source is required.
Lamp luminous efficacy, which is a measure of the efficiency at which electrical power input to a lamp is converted to visible light, varies between 13 to 51 lumens per watt of power input to the lamp, depending on the input power, and is limited by the infrared emissions. Lamps with higher input power have higher luminous efficacy.
A Xenon short-arc lamp does not require a warm-up period, and provides100% illumination shortly after ignition, which requires a relatively high (20,000 – 50,000 volt) pulse.
Since nearly have of the electrical power input to the lamp is dissipated in the lamp electrodes, the conversion of electrical power input to the lamp into incoherent broadband optical radiation is not 100% efficient. Our proprietary power conversion and control electronics and thermal management features have a test verified ignition probability of greater than 0.99, and ensure that a lamp, once ignited, is both electrically and thermally managed so that it may be continuously operated for its entire rated life, if desired.
Since a short-arc lamp is the closest possible practical implementation to an ideal point source of light, it is a source that is well suited to projection optics. Our proprietary optics capture and re-direct the optical radiation produced by the lamp into a beam that is user adjustable, typically between 1 and 10 degrees. Figure 1 shows the beam diameter, in feet, as a function of the range, in feet, for beam widths of 1 and 10 degrees. For a 1 degree beam width, the beam is highly collimated, and has a diameter at a range of 1 mile (5280 feet) is 92 feet. For a 10 degree beam width, the beam is more diffused, and may be used to illuminate a large volume of space.
Figure 1. Beam diameter vs. range
Our incoherent, broadband optical radiation supports multiple uses.
(1) Infrared Intensifier, for Night-Time Covert Surveillance: The radiation may be used, at night, to assist covert surveillance, to detect the presence of a possible adversary. In this operating mode, a first responder is equipped with night vision, and the radiation source is equipped with a black filter that blocks the visible output, so that it provides a steady beam of invisible infrared radiation. Since the responder can see but cannot be seen, he/she has a covert surveillance capability that provides a powerful situational awareness advantage over the possible adversary.
(2) General Night-Time Illumination: The radiation can be used at night to deter a possible adversary. In this operating mode, the radiation source provides a steady beam of visible pure white light. This enables a first responder to illuminate a possible adversary, to not only let the possible adversary know that a responder is nearby, but also to determine the intent of the adversary, with sufficient time to determine an appropriate level of response.
(3) Non-Lethal Weapon: The radiation may be used during the day and at night, as a light-based non-lethal weapon. In this operating mode, the radiation source provides a steady or pulsed beam of visible pure white light. The light is applied to the eyes of the adversary, which results in a temporary overload of the adversary’s optical network. As a result, the adversary is safely and painlessly distracted, disoriented, or otherwise incapacitated, and may be apprehended with relative ease.
(4) Navigation Aid for Fire Search and Rescue: The radiation source may be used as a navigation aid for fire search and rescue. In this operating mode, the radiation source is equipped with an orange filter, so that it provides a steady, highly collimated beam of orange-colored light that penetrates smoke (as well as fog). This enables fire fighters to locate trapped victims.