I am experimenting with fluorescein in NaOH3 (sodium bi-carbonate) as a gain medium for use as a regent for oil sampling. This series of tests are not done on an oil sample yet, but were done using my Prolight 1W UV LED.
fluorescein was aquired from consolidated chemical and solvents LLC and prepared in a solution of NaOH3 0.1M at a Ph of 8.4 (calibrated with a digital Ph meter.)
Fig.1 shows the raw data aquisition before processing
Fig.2 shows data after processing (subtracted from Blank.)
Fig.3 shows the data plots
What is a gain medium? Dyes
Laser dyes consist of organic molecules, which in most cases are contained in a liquid solution. (Users often make them by dissolving dye powders in some solvents.) The optical transitions of dyes are relatively broad: tens of nanometers or more – roughly comparable to those of ion-doped glasses – resulting in good wavelength tunability. A big difference between dyes and ion-doped glasses, however, is that these transitions in dyes are not forbidden; they exhibit large transition cross sections, and the upper-state lifetime is correspondingly short (a few nanoseconds). Particularly for pulsed pumping, the gain can easily become rather high, leading to amplified spontaneous emission. The saturation fluence is very low, which implies that high pulse energies can be realized only with very large beam cross sections. Despite the short energy storage time, energetic pulses can be produced if a dye is pumped with a Q-switched laser shortly before it generates or amplifies a pulse itself.
A large number of laser dyes are available, and together they cover huge wavelength regions – the full visible range and also substantial areas in the ultraviolet and infrared region (Figure 3). A dye laser can be operated with various dyes; ideally, different cuvettes and circulation systems are used for different dyes so that an easy change is possible.
Figure 3. Wavelengths that are accessible with dye lasers and additional nonlinear frequency conversion. Basically, any wavelength in a very wide range can be provided. SFM = sum-frequency mixing; MAD = (nonlinear) mixing after doubling; THU = third-harmonic unit; SHG = single-harmonic generation; DFM = difference-frequency mixing; MIR = mid-infrared.
A notorious problem with dyes is their limited lifetime; they degrade during laser operation. Dye circulation systems are usually required, enabling use of a larger volume of dye solution, which may have a lifetime of a few hundred operation hours. Also, the circulation gives the used dye the time needed to recover from so-called triplet states, where it cannot be used.
The handling of dye solutions can be somewhat tedious and involves various hazards, particularly health hazards resulting from both the dyes and the solvents. Particularly, these substances can be carcinogenic.
Solid dyes would be simpler to use, but their very limited lifetimes and the triplet state problem present serious obstacles for most applications. Source- http://www.photonics.com/Article.aspx?AID=53768
Some discussion and conclusions, I'm hoping that with this particular dye, I can come up with an adequate regent for bonding with various oil samples that seem to have a lower fluorescent threshold, without the problem of getting close or matching their wavelengths (which can be a problem, because your only going to see the fluorescence of the dye in your signal.)
I know that most gain mediums are so called "laser dyes," but I think that they can be adapted for use with UV LED's, if this is already begin done I haven't found it yet, but would love some feedback on it.
Another observation is with the regent I used (NaOH3,) is standard and the Ph was darn close,(mine was 8.4)(typical Ph for this regent at a Ph of 9 is EX:490nm EM:514nm)
my data was obviously different, I think 1 factor is the FWHM data for the LED, slit width, camera sampling rate and instrument precision problems.
Also, this is the first time ever that I have made a plot from excel, or any other program for that matter, so please just cut me a little slack...please.