ZGP – Zinc germanium phosphide
>2 J/cm2 @ 2.1 µm, 20 ns, 10 Hz | 1.9 µm – 11 µm
3photon ZGP (ZnGeP2) crystals are usually grown via horizontal gradient freeze method at high temperatures or Bridgman method. Crystals are polished and coated using either electron beam evaporation (EBE), ion assisted deposition (IAD) or ion beam sputtering (IBS) technologies. ZGP crystals have wide range of different applications in middle infrared (MIR) region – from scientific harmonic generation experiments to complex defense and military products.
- 2nd, 3rd, 4th harmonic generations of pulsed CO, CO2, chemical DF-laser and other lasers that are operating in crystal transparency region;
- Up-conversion of CO2 and CO laser radiation to near-infra-red (NIR) range by harmonics generation and mixing processes;
- Sum frequency generation (SFG) by down-conversion of Erbium (Er), Holmium (Ho), Thulium (Tm) and wavelengths to middle infrared (MIR) wavelength ranges;
- Optical parametric generation (OPG) with pumping at a wavelength of 2.0 µm;
- Defense and military applications:
- Widely used in anti-ballistic missile (ABM) and in infrared countermeasure (IRCM) systems (missile jamming), by generating optical parameter oscillation (OPO) at 2000-2100 nm to 3000-3500 nm and even 5000 nm
- Low Altitude Laser Defending System
- Producing coherent radiation in sub-millimeter range from 70.0 µm to 1000 µm.
- Medium-power and high-power applications through infrared (IR) region and terahertz (THz) range.
- Although ZGP has extremely wide transmission from 1.9 µm to 11 µm, ZGP grown with standard procedure has large absorption at 2000 nm. To solve this problem special processing procedures are required to lower the absorption value. This limits one of the dimensions of the crystal size to 6 mm only;
- Largest nonlinear coefficient from all infrared (IR) crystals (d = 75 pm/V), approximately 160 times larger than KDP;
- Mechanical and physical properties are very similar to Germanium (Ge), however ZGP is much harder than AGS or AGSe;
- ZGP can be well mechanically processed, thus good polishing quality and flatness can be achieved;
- Relatively high damage threshold;
- Phase matching available over broad spectral region with small tuning range.