get enough gain that you can don’t need the mirrors —- it’s pretty easy to build one about a foot long that can make nanosecond pulses that are about as long as the laser.
Random lasers uses random particles to extend the optical path instead of mirrors
That column had all sorts of homemade lasers. CO2, helium-neon, dye lasers...
bigiain•2mo ago
Oh man, I miss my dad's collection of a decade or two's worth of Scientific American magazines. When I was a kid in the 70s/80s, they were pure intellectual magic to me.
pfdietz•2mo ago
There was a CD (or two?) of all the Amateur Scientist columns. It may still be available through Amazon.
(The other Huygens principle is that each point on a wavefront causes another wavefront. How does that also apply to Anderson localization and optical singularities?)
> This is the key takeaway: the coherence time of the phonon (mechanical storage) is millions to billions of times longer than the coherence time of the exciton (the optical state), which is typically in the picoseconds. This is precisely why it's so attractive for quantum memory.
Todo
> Resonance: If the plasmon's wavelength fits perfectly into the length of the graphene ribbon (like a guitar string vibrating), you create a strong standing wave. The energy of the THz light is now trapped and massively amplified within this tiny graphene structure.
And also, twisting carbon nanotubes causes a bandgap which may be useful for creating transistors out of carbon.
Nano mechanical energy storage twists SWCNT;
From https://news.ycombinator.com/item?id=45951197 re: "Exploring recent advances in the versatility and efficiency of carbon materials for next generation supercapacitor applications: A comprehensive review" (2025) :
(Switching times by material: graphene: ~100s of Ghz; rGO: 1-10 GHz, SWCNT: 1-10 GHz,)
From this design chat about an integrated biorefinery chip fabrication concept, I learned that [Gemini 3 Pro] thinks there's an 80% chance that coating and drying carbon nanotubes in Lignin (or Lignin Vitrimer) would cause a sufficient bandgap in graphene: https://gemini.google.com/share/6796575598b2
> Can graphene be switched at Thz frequencies, to drive optical resonators?
[ You need all-optical switching for Thz frequencies, and also Also there are Graphene Plasmons which can be rescaled]
[ Yes, Anderson localization utilizes disorder, and Optical singularities utilize order (topology), and Isotopic Purification creates a "spin vacuum" to minimize magnetic noise ]
> Result: This is how record-breaking coherence times (seconds to minutes) are achieved in NV centers in diamond, far surpassing what Anderson localization alone typically provides
There are newer lower energy processes for fabricating lab grown diamond carbon with NV centers and color centers;
What happens when you Laser Compaction Shock (LCS) nano-mechanically twisted single walled carbon nanotubes; is there a usable (high-Q,) bandgap in twisted SWCNT, and does LCS "lock-in" that bandgap, and is that even necessary if nanomechanical energy storage in twisted single walled carbon nanotubes is lossless?
gnatman•2mo ago
sounds like a Brian Jacques superweapon
nick238•2mo ago
Am I having a stroke? Reading the title makes my head hurt.
userbinator•2mo ago
The title looked like an AI image generator prompt, and I was curious what the output image would be.
anigbrowl•2mo ago
I was perplexed too, but it turns out to be a straightforward paper on using natural materials to substitute for artificially produced ones for laser components. Birch leaves are apparently rich in carbon dots (which lase under the right circumstances) and simply stewing them yield a slurry with plenty of the desired substance. Peanuts have a molecular structure with plenty of large voids. Soak the peanuts in birch leaf slurry, excite them with a laser, and the organic medium demonstrates lasing behavior. Apparently this simpler and cheaper than the usual go-to materials, and has the potential to be manufactured with less toxic waste. I presume it's not as good as elemental materials but if it's good enough it might yield savings at industrial scale.
Yes, but if a chicken and a half laid an egg and a half in a day and a half, how long would it take a monkey with a wooden leg to kick all the seeds off a dill pickle?
slater•2mo ago
Fifteen hogsheads, of course. Fourteen if it’s a leap year.
bigiain•2mo ago
I skimmed through the article looking for pictures of trees with laser beams shooting out in every direction. Much disappoint.
chaos0815•2mo ago
first laser people have lethal allergies against...
westurner•2mo ago
"Near-Field Optical Nanopatterning of Graphene" (2025) https://onlinelibrary.wiley.com/doi/10.1002/smsc.202500184 .. https://news.ycombinator.com/item?id=45623301
Why are they random lasers?
From https://news.ycombinator.com/item?id=45949800 :
> "Cavity electrodynamics of van der Waals heterostructures" (2024) https://arxiv.org/abs/2403.19745 ; graphite / graphene optical cavity
From https://news.ycombinator.com/item?id=44922581 :
> "Grover's algorithm to efficiently prepare quantum states in optical cavity QED" (2025) https://phys.org/news/2025-08-grover-algorithm-efficiently-q...:
>> "Deterministic carving of quantum states with Grover's algorithm" (2025) https://journals.aps.org/pra/abstract/10.1103/s3vs-xz7w
PaulHoule•2mo ago
https://en.wikipedia.org/wiki/Nitrogen_laser
get enough gain that you can don’t need the mirrors —- it’s pretty easy to build one about a foot long that can make nanosecond pulses that are about as long as the laser.
Random lasers uses random particles to extend the optical path instead of mirrors
https://en.wikipedia.org/wiki/Random_laser
I studied condensed matter physics and knew a professor well who was one of Anderson’s grad students so the phenomenon of
https://en.wikipedia.org/wiki/Anderson_localization
which is relevant to random lasers is familiar to me.
pfdietz•2mo ago
https://www.jstor.org/stable/24950104
That column had all sorts of homemade lasers. CO2, helium-neon, dye lasers...
bigiain•2mo ago
pfdietz•2mo ago
westurner•2mo ago
Anderson localization ... wavefronts
/?hnlog wavefro
- Huygens-Steiner ; https://news.ycombinator.com/item?id=43673759 , https://news.ycombinator.com/item?id=44401685
(The other Huygens principle is that each point on a wavefront causes another wavefront. How does that also apply to Anderson localization and optical singularities?)
- optical singularities:
"Engineering phase and polarization singularity sheets" (2021) https://www.nature.com/articles/s41467-021-24493-y ... citations: https://scholar.google.com/scholar?cites=6348012568124728820...
- /? optical singularities and Anderson localization
TIL that optical singularities are robust and about optical vortex capture.
- metamaterials
- /? Anderson localization
"Quantum light transport in phase-separated Anderson localization fiber" citations: https://scholar.google.com/scholar?cites=2109673059927233012...
- /?hnlog Fiber
"Selective excitation of a single rare-earth ion in an optical fiber" (2025) https://opg.optica.org/oe/fulltext.cfm?uri=oe-33-19-41011 .. https://news.ycombinator.com/item?id=45620981
- /?hnlog photon
"Telecom-wavelength quantum teleportation using frequency-converted photons" (2025) https://www.nature.com/articles/s41467-025-65912-8
- /?hnlog like black holes
"Deflection of electromagnetic waves by pseudogravity in distorted photonic crystals" (2023) .. https://news.ycombinator.com/item?id=41643024
- /?hnlog metamaterial
From https://news.ycombinator.com/item?id=45715228 :
> Metamaterials and metasurfaces are probably useful for extreme nonlinear spiking neuromorphic computing with integrated nanophotonics.
> Some optical metamaterials have picosecond phase change latency
I learned that researching how to create a speckle QRNG TRNG.
Phase-change metamaterials are probably faster at whitening photonic speckle random than an FPGA.
"Traceable random numbers from a non-local quantum advantage" (2025) https://www.nature.com/articles/s41586-025-09054-3 .. https://news.ycombinator.com/item?id=45236896 :
> This protocol forms the basis for a public traceable and certifiable quantum randomness beacon that we have launched.
Here's that speckle TRNG design chat: https://gemini.google.com/share/1bb101b39c96 :
> This is the key takeaway: the coherence time of the phonon (mechanical storage) is millions to billions of times longer than the coherence time of the exciton (the optical state), which is typically in the picoseconds. This is precisely why it's so attractive for quantum memory.
Todo
> Resonance: If the plasmon's wavelength fits perfectly into the length of the graphene ribbon (like a guitar string vibrating), you create a strong standing wave. The energy of the THz light is now trapped and massively amplified within this tiny graphene structure.
And also, twisting carbon nanotubes causes a bandgap which may be useful for creating transistors out of carbon.
Nano mechanical energy storage twists SWCNT;
From https://news.ycombinator.com/item?id=45951197 re: "Exploring recent advances in the versatility and efficiency of carbon materials for next generation supercapacitor applications: A comprehensive review" (2025) :
"Giant nanomechanical energy storage capacity in twisted single-walled carbon nanotube ropes" (2024) https://www.nature.com/articles/s41565-024-01645-x
But that's at like 1-10 GHz, not Thz.
(Switching times by material: graphene: ~100s of Ghz; rGO: 1-10 GHz, SWCNT: 1-10 GHz,)
From this design chat about an integrated biorefinery chip fabrication concept, I learned that [Gemini 3 Pro] thinks there's an 80% chance that coating and drying carbon nanotubes in Lignin (or Lignin Vitrimer) would cause a sufficient bandgap in graphene: https://gemini.google.com/share/6796575598b2
> Can graphene be switched at Thz frequencies, to drive optical resonators?
[ You need all-optical switching for Thz frequencies, and also Also there are Graphene Plasmons which can be rescaled]
Which metamaterials are best for Thz all-optical switching? Are there all-carbon options? https://gemini.google.com/share/fe15869a8c9a :
> Graphene metasurfaces; highly oriented pyrolytic graphite (HOPG), Randomly oriented films of SWCNTs
Laser Shockwave Compaction might solve here; but would it destrain the bandgap out of lignin-strained CNT transistors too?
"One‐Step Transformation of Single‐Walled Carbon Nanotube Networks into High‐Performance Multilayer Graphene‐Rich Films via Laser Shockwave Compaction" (2025) https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/adf... https://westurner.github.io/hnlog/#comment-45951285
...
Are Anderson localization or optical singularities useful for maximizing state coherence time in carbon?
3.5pro: https://gemini.google.com/share/891867c0466b .. https://gemini.google.com/share/dece8f932e69 :
[ Yes, Anderson localization utilizes disorder, and Optical singularities utilize order (topology), and Isotopic Purification creates a "spin vacuum" to minimize magnetic noise ]
> Result: This is how record-breaking coherence times (seconds to minutes) are achieved in NV centers in diamond, far surpassing what Anderson localization alone typically provides
There are newer lower energy processes for fabricating lab grown diamond carbon with NV centers and color centers;
From "Scalable nano positioning of highly coherent color centers in prefab diamond" (2025) https://news.ycombinator.com/item?id=45843416 :
"Rapid, low-temp nanodiamond formation by electron-beaming adamantane C–H bonds" (2025) https://www.science.org/doi/10.1126/science.adw2025 .. https://news.ycombinator.com/item?id=45772158
"Quantum Nanodiamonds from 1 Step, Industrial-Scale Pressure and Temp Process" (2025) https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.20... .. https://news.ycombinator.com/item?id=45772190
westurner•2mo ago