Single Photon Counters - Revision history

Zhenyuan at 06:17, 9 February 2022

2022-02-09T06:17:28Z

← Older revision		Revision as of 06:17, 9 February 2022
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	* Instead, we will focus on characterizing existing APDs or photodiodes that are available.		* Instead, we will focus on characterizing existing APDs or photodiodes that are available.
	* Seems that there exist some possibly faulty or broken setups of APDs, we may look to troubleshoot them.		* Seems that there exist some possibly faulty or broken setups of APDs, we may look to troubleshoot them.
	* Example of APD characterization done by FYP student from CQT: http://www.qolah.org/thesis/thesis_janet.pdf		* Example of APD characterization done by FYP student from CQT: http://www.qolah.org/thesis/thesis_janet.pdf & masters thesis on the same topic http://www.qolah.org/thesis/LimZJ.pdf
	* From the PDF, it seems that the avalanche "pulse" can be measured directly. This begs the question: how does the shape of the pulse correlate to the photon counts?		* From the PDF, it seems that the avalanche "pulse" can be measured directly. This begs the question: how does the shape of the pulse correlate to the photon counts?
	* Problem posed by Christain: How are single photons defined/characterized?		* Problem posed by Christain: How are single photons defined/characterized?

Zhenyuan: update project

2022-02-09T04:56:59Z

update project

← Older revision		Revision as of 04:56, 9 February 2022
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	Single Photon Counting Module. (Proposed by zhen yuan, feel free to edit this page to bounce ideas/methodology)		Single Photon Counting Module. (LOOKING FOR TEAM MEMBERS) (Proposed by zhen yuan, feel free tag along/ edit this page to bounce ideas/methodology)

	==Idea==		==Idea==

	Count single photons using photoelectric effect. In simple terms, there is a semiconductor part and an electronics & signal processing part. The semiconductor part is responsible for converting the incident photon into photoelectron. The electronics is responsible for providing the bias voltage to accelerate the photoelectron to create cascading electrons. The electronics is also needed to measure the current and turn that signal into digital signals for a computer to read.		Count single photons using the photoelectric effect. In simple terms, there is a semiconductor part and an electronics & signal processing part. The semiconductor part is responsible for converting the incident photon into a photoelectron. The electronics are responsible for providing the bias voltage to accelerate the photoelectron to create cascading electrons. The electronics are also needed to measure the current and turn that signal into digital signals for a computer to read.

	==Setup/Equipment==		==Updates/Progress/Changelog==

			* 8 Feb 2022:
			* Fabrication may not be possible with current resources.
			* Instead, we will focus on characterizing existing APDs or photodiodes that are available.
			* Seems that there exist some possibly faulty or broken setups of APDs, we may look to troubleshoot them.
			* Example of APD characterization done by FYP student from CQT: http://www.qolah.org/thesis/thesis_janet.pdf
			* From the PDF, it seems that the avalanche "pulse" can be measured directly. This begs the question: how does the shape of the pulse correlate to the photon counts?
			* Problem posed by Christain: How are single photons defined/characterized?

			==Setup==

			* "test" setup:
			** photon source >> laser attenuator >> APD >> ADC >> Raspberry Pi

			* control setup:
			** photon source >> laser attenuator >> "Professional" SPCM >> ADC >> Raspberry Pi

			==Equipment needed==

	Semiconductor device:		Semiconductor device:
	* May need a semiconductor fabrication facility with the ability to make thin films on Silicon.		* <s>May need a semiconductor fabrication facility with the ability to make thin films on Silicon.</s>
	* ~~Else, we may use a~~ photodiode or ~~even an LED~~ to see how it performs.		* A photodiode or APD to see how it performs.

	Analogue electronics:		Analogue electronics:
	* Circuit design to convert analogue signal to digital signal.		* Circuit design to convert analogue signal to digital signal.

	~~==Measurements==~~		Prebuild devices/hardware:
			* laser source or photon source
	* ~~Dark room and a light source~~		* laser attenuator
	* a "~~professional~~" ~~quality~~ SPCM to ~~measure said light source~~		* computer/Raspberry Pi for data processing
	* a computer to display the results/counts.		* Analog to Digital Converter (ADCs)
			* "Professional" grade Single Photon Counting Module (SPCM) to characterize experimental setup.

	==Potential Problems==		==Potential Problems==

Zhenyuan: add write up for SPCM project

2022-01-24T11:20:46Z

add write up for SPCM project

New page

Single Photon Counting Module. (Proposed by zhen yuan, feel free to edit this page to bounce ideas/methodology)

==Idea==

Count single photons using photoelectric effect. In simple terms, there is a semiconductor part and an electronics & signal processing part. The semiconductor part is responsible for converting the incident photon into photoelectron. The electronics is responsible for providing the bias voltage to accelerate the photoelectron to create cascading electrons. The electronics is also needed to measure the current and turn that signal into digital signals for a computer to read.

==Setup/Equipment==

Semiconductor device:
* May need a semiconductor fabrication facility with the ability to make thin films on Silicon.
* Else, we may use a photodiode or even an LED to see how it performs.

Analogue electronics:
* Circuit design to convert analogue signal to digital signal.

==Measurements==

* Dark room and a light source
* a "professional" quality SPCM to measure said light source
* a computer to display the results/counts.

==Potential Problems==

* Dark noise may be overwhelming, so we may need to find a way to suppress it. (I suspect this is why commercial devices cost $2k-5k)
* Fabrication cost of the custom semiconductor device may be too high or impractical... gg.com (or we just refurbish an LED/solar panel, this will have lower PDE, but maybe we can use electronics to maximise the PDE.)
* Electronic circuitry costs. (Unlikely to be too costly)