Laser Weapons - Revision history

Lwcamp at 19:03, 7 March 2026

2026-03-07T19:03:21Z

← Older revision		Revision as of 12:03, 7 March 2026
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	==References==		==References==

	[[Category:Lasers]] [[Category:Beams]][[Category:Engineering]][[Category:Military Technology]][[Category:Warfare‏‎]]		[[Category:Lasers]] [[Category:Beams]][[Category:Engineering]][[Category:Physics & Math & Engineering]][[Category:Military Technology]][[Category:Warfare‏‎]]

Lwcamp: /* Eye safety */

2026-03-01T23:55:50Z

Eye safety

← Older revision		Revision as of 16:55, 1 March 2026
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	Even at eye safe wavelengths, the eye is more sensitive to heat than the skin. So an exposure to nominally "eye safe" light that might just cause a painfully hot sensation but no actual injury to your skin might still cook your eye like an egg.		Even at eye safe wavelengths, the eye is more sensitive to heat than the skin. So an exposure to nominally "eye safe" light that might just cause a painfully hot sensation but no actual injury to your skin might still cook your eye like an egg.

	Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the eye safe region of the UV-A band (wavelength < 0.38 μm). You'll never get complete eye safety, but you don't get complete eye safety from firearms, either, which is why shooters wear protective goggles. Some risks are inherent to the use of weapons.		Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the eye safe region of the UV-A band (wavelength between 0.32 μm and 0.38 μm). You'll never get complete eye safety, but you don't get complete eye safety from firearms, either, which is why shooters wear protective goggles. Some risks are inherent to the use of weapons.

	===Ionizing radiation===		===Ionizing radiation===

Lwcamp at 21:11, 26 October 2025

2025-10-26T21:11:31Z

← Older revision		Revision as of 14:11, 26 October 2025
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	[[File:Lasers_at_Starfire_Optical_Range.png\|500px\|thumb\|Lasers at the Starfire Optical Range.]]		[[File:Lasers_at_Starfire_Optical_Range.png\|500px\|thumb\|Lasers at the Starfire Optical Range.]]
	Lasers are common in science fiction as futuristic weapons. ~~Lasers~~ project light at damaging intensities onto a target. To be effective, this light must be focused through optics (laser beams do not travel as perfect columns! Focusing makes the beam converge to a tight spot on the target). The ability to focus is limited by [[Diffraction\|diffraction]] and, in an atmosphere, [[Thermal Blooming\|thermal blooming]]; and energy can be lost from the beam due to atmospheric [[Attenuation#Absorption\|absorption]], [[Attenuation#Scattering\|scattering]], and other phenomena. [[Lasers_and_the_electromagnetic_spectrum\|The color (wavelength, frequency, or per-photon energy) of the light you choose can be very important for your ability to get the light to the target]].		Lasers are common in science fiction as futuristic weapons. Laser weapons project light at damaging intensities onto a target. To be effective, this light must be focused through optics (laser beams do not travel as perfect columns! Focusing makes the beam converge to a tight spot on the target). The ability to focus is limited by [[Diffraction\|diffraction]] and, in an atmosphere, [[Thermal Blooming\|thermal blooming]]; and energy can be lost from the beam due to atmospheric [[Attenuation#Absorption\|absorption]], [[Attenuation#Scattering\|scattering]], and other phenomena. [[Lasers_and_the_electromagnetic_spectrum\|The color (wavelength, frequency, or per-photon energy) of the light you choose can be very important for your ability to get the light to the target]].

	Lasers can be expected to be exceptionally accurate. Depending on the power, energy, and intensity you can deliver to the target, they could be limited to relatively shallow surface burns or could drill deeply enough to reach vital equipment or organs deep inside the target. You can defend against lasers with armor or smoke, but mirroring will not work against higher intensity lasers.		Lasers can be expected to be exceptionally accurate. Depending on the power, energy, and intensity you can deliver to the target, they could be limited to relatively shallow surface burns or could drill deeply enough to reach vital equipment or organs deep inside the target. You can defend against lasers with armor or smoke, but mirroring will not work against higher intensity lasers.

Lwcamp: /* Man-portable heat ray pack */

2025-03-11T16:27:08Z

Man-portable heat ray pack

← Older revision		Revision as of 09:27, 11 March 2025
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	The heat ray pack is a weapon of the Space Marines, for use in vacuum or when boarding enemy vessels. The low recoil is considered to outweigh the limited range in atmosphere due to thermal blooming - you can keep a 1 mm spot size focus at 70 m in air even with poor air quality, and very few spacecraft corridors are anywhere near that long. In vacuum or clearer air, the heat ray can maintain its 1 mm focus up to 550 m away.		The heat ray pack is a weapon of the Space Marines, for use in vacuum or when boarding enemy vessels. The low recoil is considered to outweigh the limited range in atmosphere due to thermal blooming - you can keep a 1 mm spot size focus at 70 m in air even with poor air quality, and very few spacecraft corridors are anywhere near that long. In vacuum or clearer air, the heat ray can maintain its 1 mm focus up to 550 m away.

	Within that range, this weapon is murderous. In ~~1/10th of~~ a second, it can cut an unarmored person in half with a slash across their torso, blood and viscera splattering from the wound as explosive vaporization of tissue blasts out a 25 cm deep, 1.3 cm wide swath of destruction. Against hardened steel, sparks of molten metal fly out in an incandescent jet as the narrow beam cuts a hole up to 2 cm deep at up to 2 cm/s. Thinner steel can be cut proportionally faster. Spectra<sup>TM</sup> woven armor, effective against bullets, withers and burns under the beam as it vaporizes a 2 cm deep hole at up to 13 cm/s. Anywhere the beam penetrates leaves grievous wounds. Only hard armor provides much protection - it takes 1/10th of a second to burn a 2 cm deep hole into a rifle plate, and the beam can only cut to 2 cm depth at a rate of 1 cm/s - again, thinner plates can be cut proportionally faster. It is hard to keep a beam focused on a maneuvering target to within 1 cm for a second, so heat pack users usually aim for less armored parts.		Within that range, this weapon is murderous. In a second, it can cut an unarmored person in half with a slash across their torso, blood and viscera splattering from the wound as explosive vaporization of tissue blasts out a 25 cm deep, 1.3 cm wide swath of destruction. Against hardened steel, sparks of molten metal fly out in an incandescent jet as the narrow beam cuts a hole up to 2 cm deep at up to 2 cm/s. Thinner steel can be cut proportionally faster. Spectra<sup>TM</sup> woven armor, effective against bullets, withers and burns under the beam as it vaporizes a 2 cm deep hole at up to 13 cm/s. Anywhere the beam penetrates leaves grievous wounds. Only hard armor provides much protection - it takes 1/10th of a second to burn a 2 cm deep hole into a rifle plate, and the beam can only cut to 2 cm depth at a rate of 1 cm/s - again, thinner plates can be cut proportionally faster. It is hard to keep a beam focused on a maneuvering target to within 1 cm for a second, so heat pack users usually aim for less armored parts.

	===Anti-spacecraft laser===		===Anti-spacecraft laser===

Lwcamp: /* Man-portable heat ray pack */

2025-02-15T01:42:15Z

Man-portable heat ray pack

← Older revision		Revision as of 18:42, 14 February 2025
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	===Man-portable heat ray pack===		===Man-portable heat ray pack===

	Now let’s step a few decades into the future. Laser technology has advanced enough to allow a 10 kW laser to be fit into a 10 kg backpack with a fiber optic cable to a 4 kg beam pointer “rifle” with a 20 cm aperture. The pack is fueled by another 10 kg of high-capacity, high discharge rate [[Energy_Storage#Lithium_sulfur_batteries\|lithium-sulfur batteries]]. With 50% electricity-to-laser-light efficiency, the batteries supply enough juice for 80 seconds of continuous lasing. This laser pack is designed to emit light at ~~350~~ nm, to reduce the blinding hazard to bystanders and also to allow the beam to more easily penetrate its own plasma.		Now let’s step a few decades into the future. Laser technology has advanced enough to allow a 10 kW laser to be fit into a 10 kg backpack with a fiber optic cable to a 4 kg beam pointer “rifle” with a 20 cm aperture. The pack is fueled by another 10 kg of high-capacity, high discharge rate [[Energy_Storage#Lithium_sulfur_batteries\|lithium-sulfur batteries]]. With 50% electricity-to-laser-light efficiency, the batteries supply enough juice for 80 seconds of continuous lasing. This laser pack is designed to emit light at 365 nm, to reduce the blinding hazard to bystanders and also to allow the beam to more easily penetrate its own plasma.

	The heat ray pack is a weapon of the Space Marines, for use in vacuum or when boarding enemy vessels. The low recoil is considered to outweigh the limited range in atmosphere due to thermal blooming - you can keep a 1 mm spot size focus at 70 m in air even with poor air quality, and very few spacecraft corridors are anywhere near that long. In vacuum or clearer air, the heat ray can maintain its 1 mm focus up to ~~110~~ m away.		The heat ray pack is a weapon of the Space Marines, for use in vacuum or when boarding enemy vessels. The low recoil is considered to outweigh the limited range in atmosphere due to thermal blooming - you can keep a 1 mm spot size focus at 70 m in air even with poor air quality, and very few spacecraft corridors are anywhere near that long. In vacuum or clearer air, the heat ray can maintain its 1 mm focus up to 550 m away.

	Within that range, this weapon is murderous. In 1/10th of a second, it can cut an unarmored person in half with a slash across their torso, blood and viscera splattering from the wound as explosive vaporization of tissue blasts out a 25 cm deep, 1.3 cm wide swath of destruction. Against hardened steel, sparks of molten metal fly out in an incandescent jet as the narrow beam cuts a hole up to 2 cm deep at up to 2 cm/s. Thinner steel can be cut proportionally faster. Spectra<sup>TM</sup> woven armor, effective against bullets, withers and burns under the beam as it vaporizes a 2 cm deep hole at up to 13 cm/s. Anywhere the beam penetrates leaves grievous wounds. Only hard armor provides much protection - it takes 1/10th of a second to burn a 2 cm deep hole into a rifle plate, and the beam can only cut to 2 cm depth at a rate of 1 cm/s - again, thinner plates can be cut proportionally faster. It is hard to keep a beam focused on a maneuvering target to within 1 cm for a second, so heat pack users usually aim for less armored parts.		Within that range, this weapon is murderous. In 1/10th of a second, it can cut an unarmored person in half with a slash across their torso, blood and viscera splattering from the wound as explosive vaporization of tissue blasts out a 25 cm deep, 1.3 cm wide swath of destruction. Against hardened steel, sparks of molten metal fly out in an incandescent jet as the narrow beam cuts a hole up to 2 cm deep at up to 2 cm/s. Thinner steel can be cut proportionally faster. Spectra<sup>TM</sup> woven armor, effective against bullets, withers and burns under the beam as it vaporizes a 2 cm deep hole at up to 13 cm/s. Anywhere the beam penetrates leaves grievous wounds. Only hard armor provides much protection - it takes 1/10th of a second to burn a 2 cm deep hole into a rifle plate, and the beam can only cut to 2 cm depth at a rate of 1 cm/s - again, thinner plates can be cut proportionally faster. It is hard to keep a beam focused on a maneuvering target to within 1 cm for a second, so heat pack users usually aim for less armored parts.

Lwcamp: /* Vehicular heat ray */

2025-02-15T01:39:07Z

Vehicular heat ray

← Older revision		Revision as of 18:39, 14 February 2025
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	Let’s consider this weapon being used to burn down some incoming mortar shells. The shells are flying toward us at 200 m/s from 1 km away. The shell’s transverse speed is 50 m/s at this moment. The windspeed is 3 m/s, but with the weather, dust kicked up by the vehicles, and battlefield smoke the attenuation and absorption length in the air is about 3 km.		Let’s consider this weapon being used to burn down some incoming mortar shells. The shells are flying toward us at 200 m/s from 1 km away. The shell’s transverse speed is 50 m/s at this moment. The windspeed is 3 m/s, but with the weather, dust kicked up by the vehicles, and battlefield smoke the attenuation and absorption length in the air is about 3 km.

	Looking just at the diffraction limit, we might naively expect the laser can focus all 100 kW of its beam down to a mere 4 mm in diameter, delivering intense photonic drilling death in mere moments. But it has all this air to go through. The range is still far less than the attenuation length, so that won’t cause us to lose too much power from our beam. We’re at far too low of a frequency for two photon absorption to happen, our adaptive optics are correcting the twinkle, cascade breakdown and stimulated scattering are not a worry, and our jitter is less than our diffraction limit. But thermal blooming is going to be an issue. This early model heat ray doesn’t have fancy algorithms for predicting and correcting the non-linear effects of thermal blooming. In order to keep runaway blooming from happening, the spot size at the target can only be focused down to 15 cm at best. At this intensity, the beam is burning through the steel casing at about a quarter millimeter per second. It takes four to five seconds for the beam to burn through the case and deflagrate the explosives inside. Because it only takes five seconds for the mortar shells to reach their target, this seems to be a problem. Fortunately, as the shells get closer the beam can be focused tighter. At 800 m, the beam spot focuses down to 10 cm, and now it can burn down a shell in just over a second. With the damage done from the first second of burning, the first of the mortar shells is incinerated after two ~~second~~. Now at 600 m, the beam switches to the second shell with a 6 cm wide beam. The blistering radiant heat flashes through the second, and third shell in about half a second each. At 400 m, the beam spot is down to a mere 3 cm. The laser is blasting down the shells nearly as soon as the beam touches them. It is limited more by its rate of slew between shells than its dwell time on each shell.		Looking just at the diffraction limit, we might naively expect the laser can focus all 100 kW of its beam down to a mere 4 mm in diameter, delivering intense photonic drilling death in mere moments. But it has all this air to go through. The range is still far less than the attenuation length, so that won’t cause us to lose too much power from our beam. We’re at far too low of a frequency for two photon absorption to happen, our adaptive optics are correcting the twinkle, cascade breakdown and stimulated scattering are not a worry, and our jitter is less than our diffraction limit. But thermal blooming is going to be an issue. This early model heat ray doesn’t have fancy algorithms for predicting and correcting the non-linear effects of thermal blooming. In order to keep runaway blooming from happening, the spot size at the target can only be focused down to 15 cm at best. At this intensity, the beam is burning through the steel casing at about a quarter millimeter per second. It takes four to five seconds for the beam to burn through the case and deflagrate the explosives inside. Because it only takes five seconds for the mortar shells to reach their target, this seems to be a problem. Fortunately, as the shells get closer the beam can be focused tighter. At 800 m, the beam spot focuses down to 10 cm, and now it can burn down a shell in just over a second. With the damage done from the first second of burning, the first of the mortar shells is incinerated after two seconds. Now at 600 m, the beam switches to the second shell with a 6 cm wide beam. The blistering radiant heat flashes through the second, and third shell in about half a second each. At 400 m, the beam spot is down to a mere 3 cm. The laser is blasting down the shells nearly as soon as the beam touches them. It is limited more by its rate of slew between shells than its dwell time on each shell.

	===Man-portable heat ray pack===		===Man-portable heat ray pack===

Lwcamp: /* Eye safety */

2025-02-15T01:33:57Z

Eye safety

← Older revision		Revision as of 18:33, 14 February 2025
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	The incandescent plasma produced by an incident laser beam can also be bright enough to cause eye damage. This is less hazardous than the directly scattered light from the beam, however - similar to the danger involved with directly viewing an electric arc. Plasma also tends to emit a lot of UV light, which can also cause cataracts and photokerititis.		The incandescent plasma produced by an incident laser beam can also be bright enough to cause eye damage. This is less hazardous than the directly scattered light from the beam, however - similar to the danger involved with directly viewing an electric arc. Plasma also tends to emit a lot of UV light, which can also cause cataracts and photokerititis.

	~~Eye damage from indirect exposure~~ to the ~~beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used~~. ~~If you want~~ to ~~have~~ a ~~laser gun that can be used without worrying about blinding people without~~ eye ~~protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the higher registers of the UV-A band or shorter wavelengths (wavelength < 0.38 μm)~~.		Even at eye safe wavelengths, the eye is more sensitive to heat than the skin. So an exposure to nominally "eye safe" light that might just cause a painfully hot sensation but no actual injury to your skin might still cook your eye like an egg.

	~~Even at~~ eye ~~safe~~ wavelengths, the eye ~~is more sensitive to heat than~~ the ~~skin~~. ~~So an exposure to nominally "~~eye ~~safe" light that might just cause a painfully hot sensation~~ but ~~no actual injury~~ to ~~your skin might still cook your eye like an egg~~.		Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the eye safe region of the UV-A band (wavelength < 0.38 μm). You'll never get complete eye safety, but you don't get complete eye safety from firearms, either, which is why shooters wear protective goggles. Some risks are inherent to the use of weapons.

	===Ionizing radiation===		===Ionizing radiation===

Lwcamp: /* Eye safety */

2025-02-15T01:31:14Z

Eye safety

← Older revision		Revision as of 18:31, 14 February 2025
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	Note that part of the wavelength range of eye-hazardous light is invisible. You might never see the beam that blinds you. But every visible light laser weapon represents a threat to your eyesight.		Note that part of the wavelength range of eye-hazardous light is invisible. You might never see the beam that blinds you. But every visible light laser weapon represents a threat to your eyesight.

	The incandescent plasma produced by an incident laser beam can also be bright enough to cause eye damage. This is less hazardous than the directly scattered light from the beam, however - similar to the danger involved with directly viewing an electric arc.		Wavelengths shorter than 0.32 μm can readily cause photokeratitis (eye sunburns) and cataracts. So even though this light can't get to your retina, it can still damage your eye.

			The incandescent plasma produced by an incident laser beam can also be bright enough to cause eye damage. This is less hazardous than the directly scattered light from the beam, however - similar to the danger involved with directly viewing an electric arc. Plasma also tends to emit a lot of UV light, which can also cause cataracts and photokerititis.

	Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the higher registers of the UV-A band or shorter wavelengths (wavelength < 0.38 μm).		Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the higher registers of the UV-A band or shorter wavelengths (wavelength < 0.38 μm).

			Even at eye safe wavelengths, the eye is more sensitive to heat than the skin. So an exposure to nominally "eye safe" light that might just cause a painfully hot sensation but no actual injury to your skin might still cook your eye like an egg.

	===Ionizing radiation===		===Ionizing radiation===

Lwcamp: /* Eye safety */

2025-02-15T01:26:20Z

Eye safety

← Older revision		Revision as of 18:26, 14 February 2025
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	The incandescent plasma produced by an incident laser beam can also be bright enough to cause eye damage. This is less hazardous than the directly scattered light from the beam, however - similar to the danger involved with directly viewing an electric arc.		The incandescent plasma produced by an incident laser beam can also be bright enough to cause eye damage. This is less hazardous than the directly scattered light from the beam, however - similar to the danger involved with directly viewing an electric arc.

	Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the higher registers of the UV-A band or shorter wavelengths (wavelength < 0.35 μm).		Eye damage from indirect exposure to the beam can be avoided by wearing protective glasses that filter out the wavelength of the laser being used. If you want to have a laser gun that can be used without worrying about blinding people without eye protection, you can use short-wave infrared or longer wavelengths (wavelength > 1.4 μm) or the higher registers of the UV-A band or shorter wavelengths (wavelength < 0.38 μm).

	===Ionizing radiation===		===Ionizing radiation===

Lwcamp: /* Eye safety */

2025-02-15T01:25:29Z

Eye safety

← Older revision		Revision as of 18:25, 14 February 2025
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	===Eye safety===		===Eye safety===
	The cornea, lens, and vitreous humor of the eye are transparent to wavelengths between roughly 0.~~350~~ μm and 1.4 μm<ref>Edward A. Boettner and J. Reimer Wolter, "Transmission of the ocular media", Investigative Ophthalmology, Volume 1 Number 6, pages 776-783, December 1962 https://ec.europa.eu/health/scientific_committees/scheer/docs/sunbeds_co240n_en.pdf</ref> (the entire visible range, as well as near infrared and part of the ultraviolet-A band). Light that scatters off of your target can be focused by your very own eyes into an intense spot on your retina that can cause burns and permanent injury. Even the light that remains after multiple reflections can be hazardous. High power lasers in this wavelength range can cause instant total and permanent blindness. Anyone working with laser weapons in this range will need to take precautions to protect their eyesight. Not every eye injury will be permanent. Bright lasers can also dazzle, leave you seeing spots, or temporarily blind you. And some injuries may be permanent but only cause partial loss of vision. But this is a major concern anywhere that lasers are used<ref>Proceedings of the U. S. Army Natick Laboratories Flash Blindness Symposium, 8-9 November 1967, John M. Davies and David T. Randolph, Ed.</ref>.		The cornea, lens, and vitreous humor of the eye are transparent to wavelengths between roughly 0.380 μm and 1.4 μm<ref>Edward A. Boettner and J. Reimer Wolter, "Transmission of the ocular media", Investigative Ophthalmology, Volume 1 Number 6, pages 776-783, December 1962 https://ec.europa.eu/health/scientific_committees/scheer/docs/sunbeds_co240n_en.pdf</ref> (the entire visible range, as well as near infrared and part of the ultraviolet-A band). Light that scatters off of your target can be focused by your very own eyes into an intense spot on your retina that can cause burns and permanent injury. Even the light that remains after multiple reflections can be hazardous. High power lasers in this wavelength range can cause instant total and permanent blindness. Anyone working with laser weapons in this range will need to take precautions to protect their eyesight. Not every eye injury will be permanent. Bright lasers can also dazzle, leave you seeing spots, or temporarily blind you. And some injuries may be permanent but only cause partial loss of vision. But this is a major concern anywhere that lasers are used<ref>Proceedings of the U. S. Army Natick Laboratories Flash Blindness Symposium, 8-9 November 1967, John M. Davies and David T. Randolph, Ed.</ref>.

	Note that part of the wavelength range of eye-hazardous light is invisible. You might never see the beam that blinds you. But every visible light laser weapon represents a threat to your eyesight.		Note that part of the wavelength range of eye-hazardous light is invisible. You might never see the beam that blinds you. But every visible light laser weapon represents a threat to your eyesight.