Thorlabs APD410A2 – Si Variable-Gain Avalanche Detector, UV-Enhanced 200-1000 nm, DC-10 MHz

The Thorlabs APD410A2 is a free-space, UV-enhanced silicon avalanche photodetector with a continuously adjustable gain (M factor) and built-in temperature compensation. It’s designed for professional optical detection applications where high sensitivity and stability are key.

Key Features

• Wavelength range: 200 nm to 1000 nm (UV through near-IR) for broad spectral sensitivity.

• Bandwidth (3 dB): DC to 10 MHz, providing good measurement performance for moderate-speed signals.

• Active area diameter: 0.5 mm (for the standard version) so good for low-light/focused signals.

• Typical maximum responsivity: ~25 A/W at ~600 nm (at M = 50).

• Variable “M factor” gain from ~5 to ~50 (continuous) with temperature compensation (±3% max) for stable performance over typical lab conditions.

• Mechanical compatibility: Free-space package with mounting holes (8-32 or M4 taps depending on version) and compatibility with Thorlabs SM05 / SM1 lens-tube systems (helpful for integrating into optical benches)

• Includes ±12 V power supply (250 mA) which simplifies setup.

Applications
This detector is well-suited for:

• Optical laboratories performing spectroscopy, photon counting or low-light work.

• Research setups requiring UV sensitivity (200 nm) but still covering visible/NIR range.

• Integration into optical benches, laser setups or photonics experiments where variable gain and high sensitivity matter.