Intro to laser systems
Laser is a device that generates an intense beam of coherent monochromatic light (by stimulated emission of photons from excited atoms or molecules. Lasers have found a long series of applications in almost all areas of technology. Below are presented basic types of dual use lasers that are used in defense/security applications.
There are seven most popular military type laser systems:
- Laser pointers
- Laser illuminators
- Laser range finders
- Laser designators
- Laser seekers
- Laser spot trackers
- High energy/power lasers
Laser pointers are continuous (more rarely pulsed) lasers of that emits laser beam at narrow divergence angle ( below 1º). They typically emit lights at wavelengths in visible - near infrared range (from about 500nm to about 900nm. The aim is to create bright light spot that could be seen by friendly forces using night vision devices, VIS-NIR cameras (TV cameras) or using naked eye in case of use of visible pointers.
Laser illuminators are basically the same lasers as pointers but having different optics. Due to this change they emit laser beam in wider angle (up to about 10º). The aim is to increase illumination of area of interest at dark night conditions and to enable creation of non-noisy image of this area by VIS-NIR cameras/NVDs sensitive to light emitted by laser illuminators (typically in spectral band from about 800nm to about 1000nm. Due to similar design there are laser systems that can work in two modes: 1)pointer, 2)illuminator.
Laser range finder is a laser system that uses a laser beam to determine the distance to an object. The most common laser rangefinders operate on the time of flight principle. The distance is measured on basic of time between emission of a laser pulse by transmitter and time to record reflected laser pulse by the receiver. The aim of use is to measurement of distance to target of interest. This type o laser system is of critical importance to enable precision aiming of military weapons.
Modern long/medium range LRFs typically emit light pulses at 1550nm windows (1530nm, 1550nm or 1550nm). Some long/medium range LRFs can use 1060nm wavelength. There are also some short/medium range LRFs that operate at 910nm wavelength. LRFs that emit light pulses at 1550nm windows are considered as eye safe LRFs.
There are two main types of LRFs: 1)monopulse, 2)multipulse. The first type needs to emit only one strong pulse to measures distance (but can emit a series of such pulses). The second one needs to emit a series of lower intensity pulses to measure distance (emission time up to a second).
Laser designator is a laser system that emits a series of high intensity pulses of precisely determined temporal properties (frequency/ temporal intervals). The aim is to indicate illuminated target for laser weapons (laser seeker, laser spot tracker). The non-imaging weapons can determine precisely angular position of designated target. Laser designators typically emit light at 1060nm due to avilable pulse laser modules that offer emission of laser pulses of high pulse energy at very narrow divergence angle. Some modern designators emits light pulses in 1550nm band.
Laser seeker is a type of intelligent munitions capable to guide itself to target designated by a laser designator. The designator can be located on the same platform (aircraft, helicopter, UAV), or on other air/ground/navy platforms, or even can be used by foot soldiers.
Laser seeker head is a non-imaging system build by combining three modules: 1)quadrant photodiode, 2)optical objective, 3)gyroscope. This head gives information of relative angular position ( if target is located in one of four sectors or that is in center of field of view). Laser seeker can home
Laser spot tracker is laser system similar to laser seeker. It is built using similar laser head but is not a part of munitions but a part of airborne/ground/naval platforms. Its task is to detect in its field of view presence of a target designated by a designator (external or internal) and to slews the turret's line of sight to track movement of the target.
High energy/power lasers are lasers capable to emit laser beam of extremely high power/pulse energy that can be used as directional weapons. It can be estimated that CW laser of power over 1kW or pulse laser of pulse energy over 1J belong to this class.
Attention: this educational section have been developed to answer commonly asked questions about lasers in defense applications. However, please note that Inframet is not a manufacturer of military laser systems but a manufacturer of general purpose EO test systems. Therefore it can deliver only basic know how in field of laser systems for defense/security applications. Please contact manufacturers of military laser systems for more detail information.