13 Nd:Phosphate (Nd:Glass) rod (1053nm)
130mm long x  8mm USSR KGSS (active area 90mm) with integral mirror one end New, $40

270mm long x 10mm USSR GLS22 (active area 218mm) New, $70 for TWO,

To be built from scratch and pumped by USSR flash lamps.

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Google AI:

KGSS

​Active Ion: Trivalent Neodymium (Nd³⁺)

Host Material: Phosphate Glass matrix (Al-K-Ba Phosphate)

Luminescence Lifetime: Approx. 310–360μs (depending on the exact sub-generation batch like KGSS-0180)

Luminescence Quantum Yield: Up to 75%

Refractive Index (n): ~1.52 to 1.54 (significantly lower than Nd:YAG 1.82)
 

Using an 80mm arc lamp to pump a 90mm active section leaves a tiny 5mm unpumped gap at each end of the active zone. In your setup, this is actually beneficial for three major reasons:

 

1. It Completely Bypasses Nd-Glass Absorption Penalties

As a four-level laser system, Neodymium-doped glass is fundamentally different from a three-level ruby laser system.

Ruby: Unpumped regions intensely absorb the laser light, meaning a short lamp would kill the cavity.

Nd:Glass (KGSS): The lower laser energy level of Nd³⁺ is naturally empty at room temperature. Therefore, those two tiny 5mm unpumped active zones at the edges remain entirely transparent to the 1053nm laser line. They will not absorb your beam or ruin your gain. [1]

 

Your IFP-800 flash lamp is not too short for the KGSS; it's an ideal match for its 90mm active section.

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2. Flashlamp Arc Divergence

When the xenon gas fires, the light doesn't just shoot straight out perpendicular to the tube. Inside a reflective pump cavity (whether it is an elliptical gold reflector or a white ceramic diffuse block), the light scatters and expands outward at a slant angle. By the time the photons travel across the small gap from the lamp to the rod, the 80mm arc of light naturally spreads out, expanding its coverage to effectively fill the entire 90mm active region. [1, 2]

 

3. Protection Against Thermal Shock at the Splicing Zone

The boundary where the 90mm doped active glass physically meets the 20mm un-doped clear ends is a structural transition zone. Under heavy pulsing, the active glass heats up and expands, while the clear ends stay cool. Having the flash lamp arc be slightly shorter (80mm) ensures you are not aggressively heating the exact internal seam where the two glass types meet, significantly reducing the risk of your rod shattering from localized thermal shock. [1]

 

Original System Architecture

This pairing is historical: the IFP-800 was specifically mass-produced by Soviet factories like Razryad precisely to pump 80mm to 100mm active elements in standard industrial and military tactical laser heads (such as the Kvant family). [1, 2]

To hook up your power supply correctly, you can use the original IFP-800 operating parameters: [1, 2]

Optimal Operating Voltage: ~900V to 1600V

Self-Discharge (Explosion) Limit: 2500V

Cooling Requirement: Distilled water loop flowing at 5–8 Liters/minute. [1, 2, 3]

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GLS22

GLS means Generating Luminescent Glass. [1]

Just like your KGSS rod, a GLS22 rod is a high-power Phosphate-based Laser Glass designed by the Vavilov State Optical Institute (GOI). The Soviet Union used the "GLS" prefix followed by numbers to categorize different chemical compositions of laser glass: [1, 2]

GLS1 through GLS14 were silicate-based laser glasses.

GLS21 through GLS24 (including your GLS22) were phosphate-based laser glasses. [1, 2]

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Luminescence Lifetime: ~290–330μs.

Refractive Index (n): ~1.53 [1, 2]

Critical operating notes

Massive Flashlamp Required: To pump a 270mm long rod, you will need a massive flashlamp with a luminous arc length of at least 240mm to 250mm. A common match from the Soviet catalog for this size is the IFP-5000 (ИФП-5000) or similar high-joule linear xenon lamps.

 

Strictly Pulsed Operation: Just like the KGSS rod, the GLS22 has very poor thermal conductivity compared to YAG crystal. If you try to run it at a high repetition rate (more than a few Hertz) or high average power without a substantial liquid cooling envelope, it will shatter from thermal stress.

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The KGSS can drive the GLS22

Having high-quality Soviet phosphate laser glass opens up some spectacular high-energy project pathways that wouldn't be feasible with YAG:

 

Massive Pulse Energy: Standard Nd:YAG rods struggle to scale to the large volumes of your 270mm GLS22 rod. You can achieve much higher single-pulse energy (Joules) out of that glass rod than a typical hobby-sized YAG. [1]

 

​The Perfect Oscillator-Amplifier Chain: Your inventory is perfectly configured to build a high-power Master Oscillator Power Amplifier (MOPA) system. You can use the smaller 130mm KGSS rod as the seed oscillator and dump its output directly into the massive 270mm GLS22 rod to amplify the pulse energy exponentially. Because both are phosphate glass, their wavelengths match beautifully around 1053–1054nm

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Instead of emitting a single sharp spike, a phosphate glass laser produces a broad gain curve that peaks around 1053 nm to 1054 nm. This curve typically has a bandwidth of about 20 to 30nm wide.

When you fire the laser, it will lase stably at the specific wavelength where your cavity mirrors have the highest reflectivity and the glass has the highest gain—usually right around 1053.5 nm.

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Why This is a massive advantage

While a broad, 1053–1054nm wavelength sounds like a flaw, it is actually a benefit:

1. Ultra-Short Pulses (Mode-Locking): Because the glass supports a wide range of wavelengths

   simultaneously, you can 'lock' those frequencies together to create incredibly short, ps or fs
  pulses. Nd:YAG cannot do this well because its wavelength line is too narrow. [1, 2, 3, 4, 5]

2. Perfect MOPA Compatibility