An Inexpensive, 3D-Printable, Arduino- and Blu-Ray-Based Confocal Laser and Fluorescent Scanning Microscope

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this article the authors developed a scanning confocal thermal microscope (SCoT) by leveraging low-cost commercial. This device has the potential to be used in post-irradiation examination processes of nuclear materials. This microscope can observe both thermal and topological changes within the material. They used PHP-803T as their optical component, photodiode as detector, IR laser for external heating source, Arduino Mega board for main processing unit and stepper motors for the movement of the sample tray. Their results show that the inexpensive microscope can scan the surface of the material and detect the thermal waves.

 

I think they did a great job in designing the entire microscope and identify the potential issues and address them with fine engineering.

 

In my opinion this paper is suitable for Metrology journal with the current state. Although I have a suggestion.

 

Line 418: "Thermal wave theory predicts that at distances greater than about 5x the diameter of the laser spot size, a thermal wave has a linear slope in the phase delay between the modulated heating source and the temperature of the material away from the heating source." - Figure 14b shows a negative linear slope. Maybe you can draw the fitting line through the points. This would show the reader a clear linear relation. Also, the authors can shed some light on the reason of the outlier point, first point on the plot at the top left corner. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors introduce the development and operation of an inexpensive, 3D printable, scanning confocal thermal (SCoT) microscope. There are a few minor issues that need clarification.

1.Besides the actual photos of each component, the author should provide a schematic diagram of the entire device for readers.

2.What does COTS stand for in the keywords?

3.The operation of the device should be described in more detail.

4. Section 4.3.and Figure 14 are unclear; please explain what is the phase delay here.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript presents a low-cost scanning confocal thermal microscope. During the design process of the microscope, the author used a PHR-803 T - a similar blue-ray optical pickup head - as the light source and incorporated an additional 780 nm infrared light source for sample heating. The housing of the microscope was implemented using 3 D printing technology, and a low-cost circuit board was used in the control circuitry. The author provided a detailed description of the microscope structure in the article. Experimental validation of the developed microscope was conducted, including imaging performance tests on printed circuit board text, brass samples coated with rhodamine B ink, and synthetic spider silk. Finally, the correlation between the surface phase of a stainless steel sample with a deposited Rhodamine B film and the heating temperature was tested. The reviewer believes that the research work presented in this article will be of interest to readers developing low-cost, high-performance instruments and recommends that this article be published. Specific suggestions are as follows:

 

1. The low-cost scanning confocal microscope presented in the manuscript is intended for use in contaminating and degrading environments where components must be easily replaced. Please specify which parts of the instrument require frequent replacement.

 

2. Because components are frequently replaced or used as disposable items, the instrument must be easy to assemble and debug to ensure stability of instrument performance after component replacement. The author should provide additional information on how the instrument design ensures consistent performance after component replacement. A debugging process may even be necessary to reduce the increase in labor costs associated with each component replacement.

 

3. A complete schematic of the optical path is provided to help the reader understand the principle of the instrument.

 

4. The instrument described in this manuscript is intended for the measurement of thermal processes where the measurement of dynamic processes requires high imaging speed. Considering that the microscope uses point-scanning imaging, what is the imaging speed?

 

5. Since imaging resolution is an important technical specification for microscopes, it is recommended that the imaging resolution of the microscope be calibrated using a resolution test chart or nanoparticles.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf