One big challenge with photon detectors is sustaining sensitivity, in the presenc of large sunlight fluxes.
One way is to have small load resistors. This of course results in low sensitivity to gun/poweder_firing flashes.
Another way is to feedback the output voltage, thru a low_pass filter, and adjust the current of a constant_current_load.
This circuit is
photodiode, connects to collector of transistor; this node is the OUTPUT; cathode of diode is +5v biased (reverse biased)
NPN current source, collector to the photodiode, emitter grounded
large resistor from collector to VDD/2; this resistor size will set your gain
two large resistors in series, from collector to base
large capacitor from midpoint of the 2 series resistors, to ground
I've used this circuit a number of times, over the decades, to greatly boost the sensitivity of detection systems, because the sunlight (and 60Hz) gets mostly removed.