CW Laser Power Calculator

Calculate threshold pump power, output power, slope efficiency, and peak irradiance for CW lasers.

Continuous-wave lasers have two characteristic operating points: the threshold pump power (below which lasing does not occur) and the slope efficiency (output power gained per unit pump power above threshold). This tool computes output power, optical-to-optical efficiency, and peak irradiance at the beam waist from gain medium parameters, resonator losses, and pump conditions. It covers diode-pumped solid-state, fiber, and gas laser configurations. Use it when designing a CW laser system, verifying a manufacturer specification, or estimating beam irradiance for damage threshold assessment.

Input

Gain Medium Preset?

Pump Wavelength (λ_p)

Laser Wavelength (λ_l)

Emission Cross-Section (σ)?

Fluorescence Lifetime (τ_f)

Mode Radius (w)?

Output Coupler Transmission (T)

Internal Loss (δ)

Pump Power (P_pump)

Output Beam Waist (w_beam)?

Threshold & Efficiency

Threshold pump power

P_th

2.496W

Quantum efficiency

η_q = λ_p / λ_l

75.94%

Slope efficiency

η_s = η_q × η_a × η_c × T/(T+δ)

44.69%

Output

Output power

P_out = η_s × (P_pump − P_th)

3.353W

Peak irradiance

I₀ = 2P / (πw²)

853.9W/cm²

Abridged Optics — CW Laser Power Calculator v1.0η_a = 0.90, η_c = 0.85 · h = 6.626×10⁻³⁴ J·s · c = 3×10⁸ m/s