*3.3.1 The controls column*

The lateral column is always on screen, for each Tab selected. It is composed of two upper Controls columns and one lower indicator/comments column. On the two upper columns the user can set the parameters for different types of measurements. These two columns have been labeled "Spectral controls" and "Time controls" not because they contain only spectral or time controls (they do not) but rather to remind the user that when he/she would like to perform a spectral measurement, the software will drive the Delay Line to a specific time (so the Delay Time parameter is shown in the Spectral Controls). Similarly, when the user wants to perform a Time-scan (just as the one shown in **Figure 5**) the software will set the monochromator wavelength to a fixed specific value, and therefore this value has been inserted in the Time Controls column. In the lateral columns it is possible to set the parameters for any specific measurement. The user can define the start/stop/ step values for a time scan or a wavelength scan, the angles of polarizer and analyzer waveplates, the number of Laser shots on which the average will be performed and the number of Scans (the number of times the single measurement will be repeated to improve the signal-to-noise ratio) and finally the sample name which will be used in the experimental report. Every single value is checked together with the others in order to ensure safety. For instance if the user sets by mistake a value for stopping the Delay Line which is larger than the Delay Line length itself, the software force the value to the maximum, which has been recorded during the device initialization procedure. If the start value is larger than the stop value, the two values are

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*TeraVision: A LabVIEW Software for THz Hyper-Raman Spectroscopy*

exchanged. If the user sets a negative value for the Laser Shots parameter, it is

Below the Controls columns there are three indicators. "# per Scan" indicates the number of points to measure within a single scan, "Now scan #" indicates the number of current scan and "Meas. Numb." indicates the incremental measurements numbering. As already mentioned, each time a measurement is launched, the software creates three files using the sample name, date/time and measurement number for naming the files. Those files are saved in a folder, which is created automatically at each startup during initialization, named with the date of the measurement. The three files have all identical names but different file extensions. The \*.dat file contains all single points of the measurement. The \*.txt file contains only the averages for all points and all scans. The third file is a \*.jpeg file with the printout of

Below the indicators there are two text fields with the user name (for future references) and a free textbox in which the user will write all parameters which are not under TeraVision control (sample temperature, electric or magnetic fields applied to the sample, and so on…) and whatever observation is relevant to the present experiment. This "comment" textbox is extremely useful for creating the experimental report file. **Figure 6** shows an example of a report file. The measurement number and sample name are in the top row of the page. In the center of the page there are the graphs of the measurement, and just below them there is a textbox with all relevant parameters, the units of each column in the data files and the free comment textbox, just described above. The reason while we have chosen the \*.jpeg format instead of the more used \*.pdf file is that having one folder with up to 100 or more measurements, the user must open those 100 \*.pdf files individually in order to find the measurement he/she is searching for. Using jpeg and any picture viewer, one can just browse all pictures in the folder within the same window simply by pressing an arrow key, and it is even possible to use the preview function so that one does not need to actually open the file in order to know what is inside that specific measurement. We found that if one makes use of this report wisely and carefully, it can create a digital log-book which can partially replace the need of a physical

• The first Tab is shown in **Figure 5** is the "Acquisition" Tab. It is used for timescan, both with electro-optic detection, as in regular THz-TDS, or for scanning in time on a single wavelength in a THYR experiment, or for THz-TDS with alternative techniques such as the already mentioned ABCD technique. There are two graphs, one for the measured signal in time domain and the other which displays the Fast Fourier Transform (FFT) of the signal. In each graph two lines with different colors are displayed. The red one is the measurement on the current scan, and it is updated point-by-point, so that the user can immediately see if there are problems during the measurement without need to wait one full scan to be finished. The white curve is the average of all previous scans, and it is updated at the end of each scan. In the saved txt data file and jpeg report only the averaged curve is stored. In addition, the user has all the usual LabVIEW graph tools for changing the scale, labels, and more. Finally a vertical bar is tracing the progress of the measurement. This progress is not a theoretical estimate. It is calculated by measuring the real elapsed time since

*3.3.2 The comments columns, the saved files and the experimental report*

*DOI: http://dx.doi.org/10.5772/intechopen.96663*

forced to positive, and so on.

the experimental report.

hand-written lab-book.

*3.3.3 The Tab panel*

the core of the software, and a lateral column. This column will be always on screen for any Tab selected. Let us describe the column content, and then we will describe

The lateral column is always on screen, for each Tab selected. It is composed of two upper Controls columns and one lower indicator/comments column. On the two upper columns the user can set the parameters for different types of measurements. These two columns have been labeled "Spectral controls" and "Time controls" not because they contain only spectral or time controls (they do not) but rather to remind the user that when he/she would like to perform a spectral measurement, the software will drive the Delay Line to a specific time (so the Delay Time parameter is shown in the Spectral Controls). Similarly, when the user wants to perform a Time-scan (just as the one shown in **Figure 5**) the software will set the monochromator wavelength to a fixed specific value, and therefore this value has been inserted in the Time Controls column. In the lateral columns it is possible to set the parameters for any specific measurement. The user can define the start/stop/ step values for a time scan or a wavelength scan, the angles of polarizer and analyzer waveplates, the number of Laser shots on which the average will be performed and the number of Scans (the number of times the single measurement will be repeated to improve the signal-to-noise ratio) and finally the sample name which will be used in the experimental report. Every single value is checked together with the others in order to ensure safety. For instance if the user sets by mistake a value for stopping the Delay Line which is larger than the Delay Line length itself, the software force the value to the maximum, which has been recorded during the device initialization procedure. If the start value is larger than the stop value, the two values are

each individual Tab of the central panel in separate subsections.

*3.3.1 The controls column*

**Figure 5.**

*TeraVision front panel.*

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exchanged. If the user sets a negative value for the Laser Shots parameter, it is forced to positive, and so on.
