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Questions tagged [fluorescence]

This tag is for questions relating to "Fluorescence", an optical phenomenon in which the molecular absorption of energy in the form of photons triggers the emission of fluorescent photons with a longer wavelength.

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Is X-Ray-Emission-Containing Phosphorescence possible or is it limited to Immediate-Emission XRF?

This was a random thought that I wanted to follow up on. I know some materials can take in and kick out X-Rays in XRF (Though most x-ray scintillators tend to emit mostly visible light, not x-rays). ...
Mister SirCode's user avatar
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2 answers
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Is luminescence from impact of fast neutral atoms/molecules on a suitable substance known?

Cathodoluminescence is emission of photons by electrons impacting on a luminescent material. The Rutherford scattering experiments detected impacting helium nuclei on a phosphor screen. Many other ...
Ritesh Singh's user avatar
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Can active sonar detect objects by "fluorescence" in a different frequency from the original pulse?

Just now a bumblebee flew past me (more than a meter away), and for a moment its prominent droning sound seemed to make a vibration on my face I could feel. It made me wonder: consider a bumblebee, ...
Mike Serfas's user avatar
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Can we use prism in fluorescence microscope instead of dichroic mirror?

For the light path outlined here, if we use a prism instead of a dichroic mirror, the excitation light can also pass through the prism, but the emission filter can block the excitation wavelength if ...
nancy M's user avatar
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Why escape peak positions are calculated using emission energy and not absorbing energy?

For a X-ray monocromatic source, escape peaks energy positions are described by the difference between the incident energy and the fluorescence ($K_{\alpha}$ for example), like $E_{Escape Peak} = E_0 -...
xor's user avatar
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In fluorescence, if you excite a fluorophore with 2 wavelengths (one closer to the resonance wavelength than the other) will the emission change?

Say my fluorophore's resonance wavelength is 500nm. I excite the fluorophore with equal energies of 500nm and 550nm. The 550nm light excites the fluorophore, but is inherently weaker than 500nm ...
sjf's user avatar
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Liquids that show fluorescense for detecting 532 laser

I have used tonic water and, better, antifreeze, for aligning UV lasers with sample cells in my various setups. I am now working with 532nm and would like a similar readily available substance. I did ...
fritz's user avatar
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Convolution or addition? Proper way to model overlapping absorption line profiles

Suppose you obtain a measured spectral line shape (let's call it 'envelope') which appears as a skewed/asymmetric voigt profile. You know physically that the envelope line profile has this skew ...
kl_physicist's user avatar
1 vote
1 answer
119 views

Why do fluorescence microscopes use long-pass dichroics

Superresolution fluorescence microscopy is very sensitive to chromatic aberration. Dichroic mirrors, while being biplanar, are not normal to the optical axis and so will cause some dispersion in one ...
selene flemming's user avatar
9 votes
1 answer
383 views

Mechanism causing red fluorescence from green (532nm) laser in household glass

Background / Experiment I was surprised by this toot by @gigabecquerel, where the author shows red fluorescence in the thick bottom of a (drink) glass when exposed to a cheap consumer-grade green ...
Marcus Müller's user avatar
2 votes
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What a phosphor screen looks like after being hit by a single electron?

As I read on Wikipedia, a phosphor coating of a CRT screen lights up because an electron in one of the phosphor atoms emits light when it goes down from its excited state. When a single electron hits ...
Dmitri Urbanowicz's user avatar
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Functional form of fluorescent light flicker in time

I will start with the disclaimer that I am a mathematician and do not know much about physics. I am interested in modeling light emitted from fluorescent bulbs and am curious about the relative ...
Aaron Hendrickson's user avatar
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258 views

Can I use a radio to light a fluorescent light bulb?

I am trying to recreate the demo in this video, titled “How to create your own aurora.” To summarize the video, a radio is used to light a fluorescent light bulb. The narrator describes the walkie ...
Moth's user avatar
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2 votes
1 answer
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Is inverse quantum confinement possible?

In the "Particle in a Box" thought experiment/analogy, the reduction in volume of a cavity enclosing a particle will lead to an increase in the bandgaps energy levels that simulate that of ...
Evamentality's user avatar
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How does a scintillator work? [duplicate]

I am trying to understand how a scintillator works. Currently my understanding is this: gamma radiation interacts with atom A (through photoelectric absorption or compton scatter) which produces a ...
grace's user avatar
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1 answer
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Can phosphorescence have higher energy than fluorescence?

Our teacher has posed a question: " A 450nm photon is absorbed and two things can occur: Fluorescence at 600nm Phosphorescence at 500nm Is it possible to prove the above values? If not give an ...
jimangel2001's user avatar
1 vote
1 answer
75 views

What is the state of the light emitted by an esemble of independent single photon emitters?

Upon proper excitation, single molecules (e.g. fluorescent dyes, quantum dots, etc.) spontaneously emit single photons, namely Fock states $|1\rangle$. These states have no statistical uncertainity ...
DrManhattan's user avatar
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Thermally activated delayed fluorescence

In thermally activated delayed fluorescent (TADF) molecules, we consider 25% molecules in singlet first excited state and 75% in triplet, statistically, on electrical excitation after carrier ...
Ajeet Singh's user avatar
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79 views

Amplifying light with fluorophores

The fluorescein fluorescence spectrum shown below shows distinct excitation and emission peaks (with some overlap). If I were to "pre-charge" a fluorescein solution with a laser at ...
user1155386's user avatar
4 votes
3 answers
484 views

Why should dichroic mirrors be placed observing a certain orientation, and what happens otherwise?

I am getting very confused about the reason why dichroic mirrors should be placed observing a certain orientation. I read everywhere that you should place the mirror with the coated side facing the ...
Leo_o's user avatar
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How would you remotely detect interaction of a beam of 1 GeV protons with an aluminum sheet?

The inelastic interaction with an electron of the aluminum atom would knock them out of the atom, and would give rise to emission lines characteristic of aluminum when a free electron filled the ...
DrBunny's user avatar
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4 votes
2 answers
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Do atoms emit and absorb photons at the same wavelengths?

I know that atoms absorb photons, which promotes electrons to higher energy levels. Then upon de-excitation a photon is released. Is it true that the lines for absorption and emission spectrums are ...
theta's user avatar
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1 answer
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Why a mode-locked reduce the integration time in microscopy?

Why a mode-locked (laser) reduce the "integration time" in two-photon fluorescence microscopy?
tom's user avatar
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3 votes
3 answers
228 views

Strange Interference under monochromatic light

I'm coming to you with a strange physical/optical phenomenon I noticed today for which I'm looking for an explanation. I can't seem to find references to this, and it was pretty surprising to see for ...
mapplejacks's user avatar
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1 answer
99 views

Dependency of molecular spontaneous emission on the refractive index

I am familiar with the following equation for the spontaneous emission rate, $$ \Gamma_{em}(\omega_{if}) = \frac{\omega_{if}^3}{3\pi\varepsilon_0\hbar c^3} |\mu_{if}|^2\tag{1} $$ where $\omega_{if}$ ...
Hans Wurst's user avatar
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2 votes
1 answer
366 views

Spectrum of laser light absorbed and re-emitted by a white object

If I shine a red laser onto a white surface, I assume that: some of the red light will be nearly instantly reflected, some will be absorbed and converted into phonons and some will be absorbed and re-...
Small physicist's user avatar
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0 answers
19 views

Would UV-induced-visible-fluorescence indicate the presence of vividly reflecting UV-invisible-light?

Some people take amazing photos by using UV-induced-visible-fluorescence(UVIVF). In my understanding, we see in these photos VISIBLE light induced by UV. https://www.nationalgeographic.com/photography/...
Mitsutoshi Watanabe's user avatar
0 votes
1 answer
111 views

If not fluorescence, what is the process of emission and absorption of white light by everyday objects?

An electron in an atom is excited by a photon and moves to a higher energy state. The electron then relaxes and transitions to a lower energy state emitting a photon of longer wavelength than that of ...
Matt's user avatar
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3 votes
1 answer
160 views

How do Fluorescent molecules emit light in a different wavelength than the one needed to excite them?

if it took a very certain amount of energy to excite an atom, how come when it de-excites it emits a photon of lower energy? I know that's what scintillators do, I Just want to know the microscopic ...
Tomka's user avatar
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1 answer
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Looking for ideal calibration standards for UV / visible fluorescence

I am attempting to measure the fluorescence timing distribution (how much light is emitted over time from initial excitation) of a substance and I would like to use a solid calibrated sample (some ...
Davide Porzio's user avatar
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Reconciling two descriptions of fluorescence

I am currently studying the textbook Infrared and Raman Spectroscopy: Principles and Spectral Interpretation, second edition, by Peter J. Larkin. Section 9. Selecting the Raman Excitation Wavelength, ...
The Pointer's user avatar
3 votes
1 answer
44 views

Is there any equivalence or "fluorescence" in acoustics?

Fluorescent materials convert some visible or invisible electromagnetic radiations from a certain range of frequencies to another one, usually from higher to lower frequencies, rarely, the other way ...
adrienlucca.net's user avatar
1 vote
0 answers
70 views

Is the Crookes tube with Maltese cross (cathode rays) safe in terms of produced X rays at 5-10kV DC (1–10mA) during, say, 15 seconds of work?

I would like to get some information on the operational safety of this equipment. How much, approximately (just the order of magnitude) does the school Crookes tube with the Maltese cross, used to ...
Garatier's user avatar
3 votes
1 answer
163 views

Electronic-vibrational-rotational Transition

I'm trying to simulate the fluorescent spectrum for the first time and run into several problems. The dipole matrix element for a transition between 2 different electronic states is as follow: $$\...
jayjay's user avatar
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0 votes
1 answer
66 views

If a fluorescent atom absorbs UV and emits visible light, then how is energy conserved?

Light has a lower frequency than UV, so unless energy is also released in other forms, how can energy be conserved? What other forms is energy released as for fluorescence?
XXb8's user avatar
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4 votes
2 answers
1k views

What is the difference between lasers and fluorescense?

In both cases I see few low energetic levels, few upper energetic levels, some no-emission transitions between upper levels and main downwards transition called either fluorescence or laser. Here is ...
Dims's user avatar
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1 vote
1 answer
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Why fluorescence lifetime in laser crystals decreases while dopant concentrations increases?

I noticed, that is laser crystals the low levels of doping are used and that if higher levels did, the lifetime of excited level will be shorter. Why? The atoms of dopant are the same. Why do they ...
Dims's user avatar
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4 votes
1 answer
344 views

Can phosphors exhibit stimulated emission?

I read that phosphorescence is caused because of the presence of "forbidden" energy states. This causes the photon that is absorbed to not be immediately emitted like fluorescence but emitted after a ...
user1155386's user avatar
0 votes
1 answer
218 views

What causes a light bulb to fluoresce?

When an incandescent light bulb or fluorescent light bulb is pumped up with energy from the power grid, presumably light is subsequently emitted via transitions from the molecular excited state to it'...
Ian's user avatar
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0 votes
0 answers
40 views

Optimal paint for UV fluorescence?

If we assume that a light source with 365 nm is the optimal source for how strongly we perceive UV light when it hits a UV fluorescent surface, what would be the optimal colour to paint such a surface ...
blupp's user avatar
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1 vote
1 answer
160 views

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 ...
Tal's user avatar
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1 vote
1 answer
62 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 ...
Kagekiba's user avatar
2 votes
0 answers
123 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 ...
Rusty's user avatar
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2 votes
0 answers
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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 ...
Catchaum's user avatar
0 votes
1 answer
205 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) ...
randomguy's user avatar
1 vote
0 answers
47 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 ...
user1155386's user avatar
0 votes
3 answers
74 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?
mike's user avatar
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0 votes
1 answer
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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 ...
MsTais's user avatar
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13 votes
4 answers
3k 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 ...
Aurora Borealis's user avatar
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0 answers
29 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 ...
Post169's user avatar
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