Hi PL,
I bought a 2W 808nm diode from a Chinese supplier, the cost is about $100 USD. The diode is on a C-mount, installed in a TO-3 case, and the specifications are below.
Parameter: AL808T2000
CW output power(Mw): 2000
Peak wavelength(nm): 808+/-10
Spectral width(nm):≤5
Threshold current(mA):≤700
Operating current(mA):≤2800
Operating voltage:≤2.2
Slope efficiency(W/A):≥1.0
wavelength temperature coefficienc(nm/℃):0.3
Beam divergency(deg):12/40
Emitting area(μm):200x1
Serial resitance(Ω):≤0.25
Lifetime(h):10000
Package: TO-3
I ran the diode at a low current using a die4drive and took a photo of the emission pattern (above). The long axis of the emitter is horizontal in this photo.
I have a couple of questions...
1) From the divergence specifications and the emission pattern, I suspect that this diode has a FAC lens installed. However, I can't see any separate lens component, so I assume the FAC must be bonded to the diode facet. Is that typical?
2) Why does the emission form two stripes? I was only expecting one.
3) For C-mount diodes, why is the anode most commonly connected to the case? This seems counterintuitive, because it requires a negative power supply rail when the case is grounded.
4) I realise this diode is intended for pumping YAG, where the beam shape is non-critical, but I want to focus the emission to a small spot for laser marking. Is a single plano-convex lens a reasonable way to do that?
As always, any and all input is welcome!
Best regards,
weartronics