banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
A low-noise large dynamic-range readout suitable for laser spectroscopy with photodiodes
Rent this article for
View: Figures


Image of FIG. 1.
FIG. 1.

Simplified schematic diagram of a negative-feedback current preamplifier. The photodiode current is turned into a voltage through feedback resistor RF. Stray capacitance CS sets the dominant pole of the preamplifier, which dictates the circuit's bandwidth.

Image of FIG. 2.
FIG. 2.

Prior art. The dc gain is lower than the ac gain, thanks to the feedback path through R1, C, and R2.

Image of FIG. 3.
FIG. 3.

New solution. The main change is the insertion of a proportional-integrative (P-I) block along the feedback loop, which yields complete removal of the output voltage offset.

Image of FIG. 4.
FIG. 4.

Four-channel prototype of the circuit. Four 1 mm2 silicon PIN diodes are mounted on the front panel. The preamplifiers are realized in hybrid technology on alumina substrates.

Image of FIG. 5.
FIG. 5.

Response of the circuit to a step current pulse with (upper curve) or without (lower curve) dc cancellation device.

Image of FIG. 6.
FIG. 6.

Response of the circuit to an input step current as observed in the ms time scale. It is an exponential decay with a decay time constant of about 100 μs.

Image of FIG. 7.
FIG. 7.

Noise waveform observed at the preamplifier output when the photodiode is lighted in such a way to deliver a current of ∼60 μA. The rms noise is lower than 1 mV.

Image of FIG. 8.
FIG. 8.

Response of the four circuit channels to the optical signals caused by a ∼0.7 μm diameter particle traversing the laser beam at a speed of ∼140 m/s. The electronic noise as represented in particle size units is ∼10 nm rms.


Article metrics loading...


Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: A low-noise large dynamic-range readout suitable for laser spectroscopy with photodiodes