Single photon counting experiences

[lalbatros]

Hello,

Single photons counting is daily life since decades in nuclear physics: gamma rays and X-rays are detected individually since very long. Solid-state detectors are the most used.

In the visible part of the spectrum, this is becoming daily life also. Detectors have reached very high efficiency.

I guess that in the microwave or radiowave spectrum single photons counting is not so mainstream or even impossible.

Would some of you know what are currently the lowest frequencies (or energies) where single-photons detections have been performed? Have single photon detectors been built for millimeter waves, for example? Could you also indicate what are the limitations or difficulties and their physical reasons?

Thanks,

Michel

 

[eljose79]

Hello Michel,

Thank you for bringing up this interesting topic! Single photon counting has indeed been a common practice in nuclear physics for many years, as gamma rays and X-rays are often detected individually. Solid-state detectors, such as scintillation detectors and semiconductor detectors, are commonly used in these applications due to their high efficiency and sensitivity.

In recent years, single photon counting has also become more prevalent in the visible part of the spectrum. With advancements in technology, detectors have been developed with very high efficiency in this range. However, as you mentioned, the use of single photon counting in the microwave or radio wave spectrum is not as common or even possible due to some limitations and difficulties.

Currently, the lowest frequencies where single photon counting has been performed are in the terahertz range, which is between the microwave and infrared regions. Single photon detectors have been developed for this range, but they are still in the early stages of development and have not been widely used.

One of the main limitations for single photon counting in the microwave and radio wave spectrum is the low energy of these photons. This makes it challenging to detect them individually, as the energy levels are much lower compared to gamma rays and X-rays. Additionally, the longer wavelengths of these photons make it difficult to design detectors that are sensitive enough to detect them.

Another difficulty is the background noise in these frequency ranges. The Earth's atmosphere and other sources emit a significant amount of radiation in the microwave and radio wave spectrum, making it challenging to distinguish single photons from the background noise.

Overall, while single photon counting has become a daily practice in some areas of physics, it is still a challenge to extend this technique to the microwave and radio wave spectrum. However, with continued advancements in technology and detector design, it is possible that we may see more widespread use of single photon counting in these frequency ranges in the future.

I hope this helps answer your question. Let me know if you have any further inquiries or if you would like to discuss this topic further.

 

[denian]

Hello Michel,

Thank you for your question about single photon counting experiences. As you mentioned, single photon counting has been a common practice in nuclear physics for many years. However, it is now becoming more prevalent in other areas of science, such as visible light detection.

In terms of the lowest frequencies where single photon detection has been achieved, it has been reported that single photons have been detected in the millimeter wave range (around 30 GHz). This was achieved using superconducting detectors, which are capable of detecting single photons with high efficiency. However, there are still challenges and limitations in detecting single photons at these frequencies. One of the main difficulties is the low energy of the photons, which makes it harder to distinguish them from background noise. This is because the energy of a photon is directly proportional to its frequency, so lower frequencies mean lower energies. Another difficulty is that millimeter waves can be easily absorbed by materials, making it challenging to design detectors that are sensitive enough to detect single photons without being overwhelmed by background noise.

In addition to these technical challenges, there are also physical limitations that arise from the nature of single photons. For example, single photons are inherently random and cannot be predicted or controlled, which makes it difficult to accurately measure their properties. This is why single photon counting experiments often require large numbers of photons to be detected in order to obtain reliable results.

Overall, while single photon counting has been successfully achieved at low frequencies such as millimeter waves, there are still many challenges and limitations that need to be addressed. With advancements in technology and research, it is possible that we may see even lower frequencies being used for single photon detection in the future.

I hope this information helps answer your question. Thank you for your interest in this topic and for your contributions to the scientific community.