ss-Raman-GUI

UI, data collection, and spectral math for perfoming spread spectrum (surface-enhanced) Raman measurements. Designed to implement the method described by Lee et al. Automates the process of controlling a function generator and spectrometer to collect data and performs the necessary FFT's and automatically processes the data produced.

Usage

Most of the controls should be self-explanatory, but for clarity:

• Data Directory: Absolute path to where data files should be stored
• Data Filename: Name for the output files, note that suffixes will be automatically appended -- _raw, _pn_fft, _final with numbers for multiple scans (e.g. filename_raw_0.txt). Files will be automatically overwritten if the same filename is used for subsequent runs. Output data is comma separated in the format: Frequency (cm^-1), Intensity (counts or arb.)
• Select a Spectrometer: Select a spectrometer from the list to use for this measurement
• Re-scan for spectrometers: Re-scans ports for attached spectrometers (if you attach a spectrometer once the program has started)
• # of Measurement Repetitions: For performing multiple measurements sequentially
• PN Bit Length: How many bits should be used to generate the pseudorandom noise sequence? Generally more is better, but the improvement saturates
• Integration Time: How long should the spectrometer acquire a spectrum for (in milliseconds)?
• Modulation Frequency: How fast should the function generator adjust the laser power (in MHz)? Generally want this as fast as your function generator / electro-optic modulator can handle
• File output options:
  • Raw Data saves the raw data from the spectrometer, generally useful for diagnosing the system and making sure things are working as expected
  • PN FFT Data is the Fourier Transform of the PN noise sequence, also generally useful for diagnosing issues with the system or with the code
  • Finalized Data is the point-wise multiplication of the above, and is generally the "actual" output from the measurement
• Start Scan: Unsurprisingly, starts a measurement. Entries in the other choices are fixed at the time the scan starts and changes will not be honored. Changes to "Stop Scan" while a measurement is in progress, to end it early. Note that it can only end a measurement after a complete measurement (that is, this only stops early if you have more than one Measurement Repetition(s))
• Scan Progress: Progress bar for the whole measurement (including all repetitions). Should always overestimate how much time remains

Compilation

The application is built using GTK3 for the UI and FFTW to perform Fourier Transforms. For the specific equipment we use, we also need the DAx-22000 library from Wavepond which contains all the necessary pieces on it's own. We also have a QE-Pro from Ocean Insight and communicate with it using the Seabreeze API. For compilation on Windows, I used Mingw-w64. GTK and FFTW have native mingw-w64-x86 packages and the Wavepond library "just worked" for me, but compiling the Seabreeze library required a few extra steps. In particular:

1. Install the mingw-w64 libusb and libusb-compat and then moved the installed usb.h file up one level into the main include folder in your mingw location
2. Inside the Seabreeze common.mk file, made the following changes:
3. Remove -Werror as there are some errors which can be safely ignored that I wasn't in a position to fix
4. Modified the Mingw-32 block to link against the correct libraries: -lusb, -lstdc++, -lwsock32, -lm and the installed version of mingw64 -L/path/to/msys64/ming64/lib
5. Added line CFLAGS_BASE += -D _WINDOWS -D BUILD_DLL to indicate that we are on Windows and are building the DLL
6. Modify the root Makefile under lib/libseabreeze.$(SUFFIX): initialize to reorder some of the arguments as the order matters for gcc/g++: $(CPP) lib/*.o $(LFLAGS_LIB) -o $@

Customization

The code is designed to be relatively easy to adopt for a different combination of spectrometer (currently uses an Ocean Insight QE-Pro) and function generator (Wavepond DAx-14000). To do this, the code in spectrometer_functions.c and waveform_gen.c are the only places that should need to be changed to use a different API. As long as the replacement files provide the functions specified in spectrometer_functions.h and waveform_gen.h you can rewrite those files as needed. Additionally, the values in measurement_params.h will need to be adjusted for your specific system (particularly laser wavelength).