Microchip Lasers Using Nd:YAG and Nd:YVO4 Crystals
What is a microchip laser?
A microchip laser is a diode-pumped solid-state laser built with an extremely short cavity: a thin gain crystal and (usually) a saturable-absorber Q-switch held in optical contact, often diffusion-bonded into one monolithic assembly. The short cavity gives a single longitudinal mode and, with a passive Q-switch, produces short, high-peak-power pulses from a tiny, rugged package. Nd:YAG and Nd:YVO4 are the two most common gain media.
Nd:YAG vs Nd:YVO4 microchip lasers
Nd:YAG microchip lasers store more energy (longer upper-state lifetime) and produce higher pulse energies, while Nd:YVO4's very high pump absorption and gain suit the shortest, lowest-threshold designs. Both are typically Q-switched with Cr4+:YAG, and the absorber is frequently bonded directly to the gain crystal (e.g. Nd:YAG / Cr4+:YAG / YAG) — the textbook application of diffusion bonding.
| Feature | Microchip laser |
|---|---|
| Cavity | Very short (gain + absorber in contact/bonded) |
| Output | Single longitudinal mode, passively Q-switched pulses |
| Typical gain media | Nd:YAG (higher pulse energy), Nd:YVO4 (lowest threshold) |
| Q-switch | Cr4+:YAG (see our Q-switch comparison) |
| Package | Compact, rugged, alignment-free |
Applications
Microchip lasers are used for laser rangefinding and lidar, target designation, LIBS and spectroscopy, and as seed sources — anywhere a small, low-power pump must yield short, high-peak-power pulses. See our Cr4+:YAG vs Co:Spinel vs V:YAG comparison for the absorber choice and the Nd:YAG vs Nd:YVO4 vs Nd:YLF comparison for the gain choice.
Frequently asked questions
Why are microchip lasers single-frequency? The extremely short cavity supports only one longitudinal mode, giving a clean single-frequency pulse.
How are the gain and absorber combined? Usually by diffusion bonding into one crystal (e.g. Nd:YAG/Cr4+:YAG/YAG), removing alignment and enabling the short cavity.
Nd:YAG or Nd:YVO4? Nd:YAG for higher pulse energy; Nd:YVO4 for the lowest threshold and most compact builds.
For more information on crystal materials, please consult info@aogcrystal.com