Responsivity and Noise Equivalent Power of a Single Cold-Electron Bolometer
Round 1
Reviewer 1 Report
expand abstracts, with respect to the state of the art and the topic studied.
increase, if possible, the number of references
introduction
explain what a CEB is for, describe the state of the art.
What are the problems in using the CEB
improve the quality of figure 1
broaden the discussion,
specify the contribution of the authors in the treated topic (it is a very sectorial topic).
why the input power was varied was modulated from 35 Hz to 2 kHz.? what happens if you go down in frequency or go up in frequency.
Why do you have this frequency range?
Why does frequency come into play?
In the conclusions explain the future development of the topic
Author Response
Dear Reviewer,
Thank you very much for your comments and suggestions to improve our paper. They are highly appreciated. We have made revised the paper accordingly, and below are our replies to your comments.
- Expand abstracts, with respect to the state of the art and the topic studied.
Done.
- Increase, if possible, the number of references
Done. References to TESs and KIDs were added.
- In the introduction
- Explain what a CEB is for, describe the state of the art.
The concept of the CEB is described in the 1st and 2nd paragraphs of the Introduction.
- What are the problems in using the CEB
The main problem of CEB is matching with SQUID readout due to relatively high resistance to create array of bolometers with multiplexing. Included.
- Improve the quality of figure 1
Figure 1 has been improved and a AFM image of the device was added to better aid the reader in understanding its physical structure and components.
- Broaden the discussion
Done.
- Specify the contribution of the authors in the treated topic (it is a very sectorial topic).
The author contributions have been specified in the Author Contributions section of the article, just after the Conclusions.
- Why the input power was varied was modulated from 35 Hz to 2 kHz.? what happens if you go down in frequency or go up in frequency.
The 1/f noise is limiting factor to do down in frequency and a bandwidth of the amplifier is limiting factor to do up in frequency.
- Why do you have this frequency range? Why does frequency come into play?
The reason is to find optimal frequency range with minimum contribution on the amplifier.
- In the conclusions explain the future development of the topic
Done.
Reviewer 2 Report
The authors report on noise measurements of a single pixel cold electron bolometer to, primarily it seems, corroborate recent measurements and results on arrays of cold electron bolometers. After fabrication using ebeam lithography and thin film metal deposition, they characterize the device response at low temperatures in a dilution fridge. The results show that the single pixel cold electron bolometers have very low noise equivalent power in the 10^-18 W/Hz^1/2 range.
I think the results are sound and the conclusions are justly supported throughout. I think some time and additional images could have been given to describing the devices and the measurements in more detail to help the reader. I have the following more specific requirements. If the authors first address these, I think the paper could be considered for publication.
- In the fabrication details, it would be highly beneficial to have an image (optical, scanning electron microscopy, or atomic force microscopy) of the device. This would help with understanding not only the fabrication, but also the measurements later in the article. For instance, when the authors describe the inner and outer tunnel junctions, these could be shown on an image directly.
- I am curious why there is limited experimental data below 450 ueV. It would be nice to see the full evolution of these curves, especially because they are being compare with theory.
- Please explicitly define the terms in equations 1 and 4. It should not be assumed that the reader understands all variables presented without definition.
Author Response
Dear Reviewer,
Thank you very much for your comments and suggestions to improve our paper. They are highly appreciated. We have made revised the paper accordingly, and below are our replies to your comments.
The authors report on noise measurements of a single pixel cold electron bolometer to, primarily it seems, corroborate recent measurements and results on arrays of cold electron bolometers. After fabrication using e-beam lithography and thin film metal deposition, they characterize the device response at low temperatures in a dilution fridge. The results show that the single pixel cold electron bolometers have very low noise equivalent power in the 10^-18 W/Hz^1/2 range.
I think the results are sound and the conclusions are justly supported throughout. I think some time and additional images could have been given to describing the devices and the measurements in more detail to help the reader. I have the following more specific requirements. If the authors first address these, I think the paper could be considered for publication.
- In the fabrication details, it would be highly beneficial to have an image (optical, scanning electron microscopy, or atomic force microscopy) of the device. This would help with understanding not only the fabrication, but also the measurements later in the article. For instance, when the authors describe the inner and outer tunnel junctions, these could be shown on an image directly.
Figure 1 now includes an AFM image of the CEB labelled as Figure 1c, and the figure caption was correspondingly revised, as well. The structures are labelled by color to better aid the readers in understanding the images.
- I am curious why there is limited experimental data below 450 ueV. It would be nice to see the full evolution of these curves, especially because they are being compare with theory.
All measurements were done in current-biased mode. Thus, there is a higher spread in the data points as a result of very high resistance from zero bias to about 450 meV.
- Please explicitly define the terms in equations 1 and 4. It should not be assumed that the reader understands all variables presented without definition.
Descriptions have now been provided for the variables in each of the equations.
