Ten Key Facts About LBO Crystal: Properties, Applications, and Manufacturing

Key facts about LBO

LBO (lithium triborate, LiB₃O₅) is one of the most important nonlinear crystals for frequency conversion. The facts below summarise why it is so widely used, and where its limits lie.

1. High laser-damage threshold. LBO has the highest damage threshold of the common nonlinear crystals (BBO, LBO, KTP), which is why it leads high-average-power conversion.
2. Broad transparency (~160–2600 nm). It transmits from the UV into the near-IR, supporting SHG, THG and OPO across the Nd-laser range.
3. Moderate nonlinearity (d_eff ~0.8–1.2 pm/V). Lower than KTP or BBO, so longer crystals or tighter focusing are used — the trade-off for its damage threshold.
4. Supports non-critical phase matching (NCPM). Temperature-tuned NCPM removes walk-off and widens angular acceptance — ideal for high-quality beams.
5. Used for 1064→532 and 532→355 nm. The backbone of green and UV generation from Nd lasers.
6. Good for OPCPA. Broad phase-matching bandwidth plus damage resistance make it a favourite ultrafast parametric stage.
7. Slightly hygroscopic. Less so than BBO, but protected coatings and storage still matter.
8. Grown as large, high-quality boules. Good optical homogeneity is achievable at useful apertures.
9. Lower efficiency than KTP at low power. For compact, low-power green, KTP is usually more efficient.
10. Cannot reach deep UV on its own. For 266 nm, CLBO or BBO are typical instead of LBO.

See our BBO vs LBO vs KTP comparison, the LBO high-power article, and the LBO product page.