Questions tagged [fluorescence]

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Is it possible to make a fluorescent material that only glows in response to a specific UV wavelength?

There are any number of fluorescent materials that glow when exposed to UV light. But what if I wanted such a material that only glows in response to very specific wavelengths, emitting no visible ...
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21 views

fluorescence wavelength limit

My understanding is that fluorescence occurs when light has sufficient energy to excite an electron, which then emits a different photon (always with a larger wavelength) and releases the energy it ...
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57 views

What is the nature of vibrational relaxation in fluorescence?

Electrons in fluorescent substances get excited from the ground state($S_o$) to the first excited state($S_1$) or higher excited states in case of upconversion. Depending on the statistical ...
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33 views

Timescales of plasma recombination and fluorescence?

I am currently working on a very simple model for the radiation from electric arcs. As both fluorescence (internal electronic transition) and plasma recombination occur, I would like to compare the ...
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1answer
44 views

Photon Spin in Fluorescence and Phosphorescence

I think i still lack basic understanding of how absorption and emission of light actually works. Like fluorescence is the radiative transition from an excited singlet state to the ground (singlet) ...
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21 views

Requirements for a fluorescent medium to provide optical gain

I have seen fluorescent material such as Rhodamine 6G being used as a gain medium in dye lasers. My understanding is that by pumping the medium with energy, we can make stimulated emission happen ...
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3answers
47 views

Why is there not a solid state fluorescent lamp?

Is it possible to coat a solid piece of metal with fluorescent powder (such as in a tube), and get this to emit light in a strong electric field?
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1answer
46 views

DNA - optical response and fluorescence

I am curious about the state of affairs with the DNA fluorescence. I know that there was some initiative in physics community in 1980's and 1990's, but some authors question even whether DNA molecules ...
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4answers
2k views

If blackbody radiation at 6000K peaks in the optical, why aren't fluorescent bulbs at 6000K?

We know, via Wien's law, that a body at 6000K emits an electromagnetic wave at the peak wavelength in the visible spectrum. How come say the fluorescent tubes which also emit the EM waves that we can ...
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23 views

Fluorescence photons per event

When a high-energy photon hits a material that fluoresces, what formula can you use to determine how many photons will radiate out as the material de-excites? I would like the most general formula ...
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49 views

Cannot observe Raman signal from Styrofoam

I am trying to build a low cost Raman spectrometer. I am using a refurbished B&WTek spectrometer that I purchased from eBay. I calibrated the unit myself and found to be very sensitive and ...
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0answers
37 views

What are some mechanisms that can lead to unexpected/anomalous spectral lines

I am studying fluorescent spectroscopy (laser-induced fluorescence spectroscopy specifically). In a particular atomic spectrum, there are some unexpected lines not associated with any known ...
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1answer
182 views

Can a plasma ball light up minerals that fluoresce?

I want to know if I could use a plasma ball to light up a UV poster that are typically activated by blacklights. option 1: using light from the globe According to my research it seems that the light ...
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32 views

Two-photon absorption fluorescence of air

I'm wondering if there are any major constituents of air which are capable of undergoing two-photon absorption and ultimately fluorescing in the visible spectrum. The original wavelengths of the ...
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1answer
45 views

Fluorescence or phosphoresence?

Is there any theoretical way to know if a material emits a fluorescent light or a phosphorescent one? Is there any relationship between this process and the singlet-triplet energy splitting $\Delta E =...
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1answer
341 views

Raman Scattering vs. Fluorescence (1-photon / 2-photon process) [duplicate]

I have a question considering the difference between Raman Scattering and fluorescence. I know that Raman Scataring is a non-resonant process, while fluorescence is resonant, that Raman scattering ...
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258 views

Why is a white LED color spectrum more continuous than CFL spectra?

As far as I understand, white LEDs and CFLs both use phosphor mixtures to convert part of their primary emission spectrum to longer wavelengths. What puzzles me is the difference in the resulting ...
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70 views

“Fundamentalrelation of Resonance Fluorescence” - How can it be?

In my quantum optics lecture, I was given the formula: $$ \vec{d}_{eg} \hat{\vec{E}}^{(+)} = \frac{i \kappa \hbar}{2} | g \rangle \langle e | $$ Here, $\vec{d}_{eg} = \langle e | \hat{\vec{d}} | g \...
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1answer
45 views

Is it valid to compare experimental data and theoretical data like this? Does the vertical axis of the graphs have to correspond?

The plotted curve is the experimental value of the SPD curve. Though it doesn't look "spikey" as it should, stacking the image on top seems to explain that the data is infact correct, but that more ...
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1answer
209 views

Can heat cause flourescence or phosphorescence at STP?

I am aware that chemical reactions may cause fluorescence. Most fluorescence results from adding light and then watching the captured light re-emit. Is there any that doesn't require adding light, ...
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3answers
2k views

What are these alternating bright and dark rings in fluorescent lamp?

I'm quite surprised by these regularly spaced rings of alternating brightness in a fluorescent tube. These are also moving along the tube and only appear when the voltage is low. What are these and ...
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37 views

Limits single fluorophore, simultaneous absorption and emission

So I've been trying to find out what the limitations are for single fluorophores. What I know is that a fluorophore is excited by a photon in too a higher excited state, it then relaxes and later ...
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46 views

Collisional quenching in fluorescence

I am studying collisional quenching phenomenon in fluorescent measuring and I am focusing on Stern - Volmer relationship. I can't understand why the ratio of the intensities of fluorescence is equal ...
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1answer
54 views

Can we have a three-level system with mixed parity and transition dipole moments in different directions?

I would like to know if there are molecules described by a three-level system with mixed parity and transition dipole moments in different directions. By mixed parity I mean all three transitions can ...
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34 views

What upconversion phosphor is this?

Is there a way t know which upconversion phosphor was used to create this? The original flickr image doesn't offer any information. If this is impossible, where can I find any images demonstrating a ...
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1answer
227 views

Uranium-doped solid state visible lasers - feasible?

It is known that uranium glass shows strong green fluorescence under near UV illumination which could promise green lasers without non-linear crystals. Is it feasible to build Uranium doped laser (...
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1answer
482 views

Raman vs Fluorescence, scattering vs absorption, classical vs quantum [duplicate]

I am trying to grasp the difference between Raman scattering and fluorescence. To me it appears that the former is described in a somewhat more classical context as ordinary inelastic scattering, ...
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22 views

Discharge on fluorescent light

when the voltage is very low, fluorescent lights will not light fully as the voltage is not enough to generate a discharge. But I could see a glow at both the ends. When I touch on the outside of the ...
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1answer
137 views

Which of these reasons are causes for the Stokes effect in Raman Scattering and/or Luminescence?

I’ve read several reasons for the Stokes effect and I can’t make out which of these are the true causes. Which of these apply to Raman or Luminescence or both? Are some of these the same thing? 1. ...
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2answers
313 views

How is the resolution of a Laser Scanning Microscope defined?

I am reading about the image formation process in fluorescence microscopy, and I am puzzled by a question. Why the axial resolution of a Laser Scanning Microscope depends on excitation wavelength, but ...
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51 views

What are the energy levels responsible for CdSe's fluorescence

Fluorescence is when a material absorbs photons of one wavelength and radiate photons of another wavelength (necessarily lower due to conservation of energy, assuming the material is unchanged). CdSe ...
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1answer
193 views

Are there any fluorecent materials that absorbs infrared light and re-emit in the visible spectrum

I understand certain phosphors will absorb ultraviolet light and then re-emit in the visible spectrum, for example "glow in the dark" paint and toys. Are there any material that go the other way ...
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2answers
154 views

Do fluorescent white materials exist?

From my understanding of fluorescence, a "fluorescent yellow material" (like in highlighters) is a material that contains yellow dyes and fluorescent dyes absorbing green to give yellow. Then, the ...
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2answers
417 views

Fluorescence and phosphorescence

Fluorescence is where UV light is absorbed then emits visible light right? Is it that you can only see it in the dark whereas phosphorescence is where UV light is absorbed and visible light is ...
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647 views

Why does fluorescence emission detector pick up second order wavelengths with first order scan, even though they have different angles?

my question in more detail and with an example: Let's say I have a 980nm laser and I use that laser to excite my fluorescent solution in cuvette. My scan range is from 300 to 800nm. If, for example I ...
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648 views

Why self-quenching (aka concentration quenching) of fluorophores is possible?

In some cases, increasing the concentration of a fluorofore results in reduced fluorescence, due to self-quenching (aka concentration quenching). (source) On the other hand, self excitation supposed ...
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338 views

Why singlet and triplet states are not mentioned when dealing with inorganic semiconductors or other heavy materials?

Singlet and triplet states get attention in organic materials (fluorescence, phosphorescence, upconversion). Why singlet/triplet states are never mentioned in the context of inorganic semiconductors, ...
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157 views

Do we know how much energy is released in internal conversion (fluorescence)?

In the Jablonski Diagram, when photons hit a surface and certain frequencies are absorbed, then internal conversion occurs to the excited portions of the surface and energy is released as heat (If I ...
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70 views

How can I determine if a peak in a spectrofluorometer's spectrum is erroneous?

Let me give you the specific scenario since I'm really not sure which factors are relevant or not: Our lab made our own upconversion nanoparticles (UCNP) following a popular paper on the subject. ...
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1answer
30 views

How can I simulate two fluorophores with a reticle?

Fluorophores typically emit in an incoherent fashion. I thought I could simulate two fluorophores (e.g. single molecule fluors) with a reticle. My concept was to make two small holes in a chrome ...
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1answer
50 views

Interpretation of different values of antibunching

When the frequency resolved second order correlation function at zero time delay, $$g^{(2)}(\omega_1, \omega_2) = \frac{\langle a_1^\dagger a_1(t) a_2^\dagger a_2(t)\rangle}{\langle a_1^\dagger a_1(t)\...
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2answers
489 views

Is it possible to mix a luminescent drink? [closed]

Is it possible to create a drink that glows? In other words, is it possible to create a non-poisonous drink that fluoresces? Are there known compounds suitable for that? If not, then what about a ...
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1answer
489 views

How do white neon lights work?

I was under the impression that neon lights work by fluorescence and therefore work by emitting a certain wavelength of light. neon produces an orange color, hydrogen a red color. Supposedly, they use ...
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95 views

Visible wavelengths of air fluorescence data - needed for school demo laser telephone design

I'm seeking information about fluorescence in visible wavelengths (390-700nm) of any of the main constituents of air ( $ N_2, O_2, CO_2, H_2O, CO, etc. $) that can be excited with a (hopefully low-...
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1answer
910 views

Difference between Rayleigh scattering and fluorescence spectroscopy [closed]

How can we differentiate Rayleigh scattering from fluorescence spectrum?
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46 views

How fast can a fluorescent lamp flicker

Using electronic ballasts, the current frequency is boosted up to 60 kHz in some models. Does the fluorescent lamp continue to flicker at that frequency or does it produce continuous light? In this ...
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104 views

Any suggestion of laser pointer for everyday life study of fluorescence?

I want to buy a laser pointer to study fluorescence in my kitchen. Any suggestion? What kind of laser pointer? What stuff for demonstration?