作者luben (魯蛇中的魯蛇)
看板Physics
標題[問題]幾個光學問題
時間Mon Apr 24 00:01:03 2017
1.A commercial pulsed Titanium-Sapphire laser could produce a pulse train with
80MHz repetition rate of 300 femtoseconds (FWHM) Gaussian pulses around 800 nm with
average power of 2.5 Watt.
If another laser is producing a continuous wave (CW) with the same average
power of 2.5 Watt and at 800 nm wavelength as this pulsed laser,
Question: For two-photon excitation experiments, which laser (pulsed or CW one) is the
better choice, why?
感覺是跟photons的數量有關,算起來pulsed的photons較高
請問是這樣嗎?
依常理判斷,通常是CW較佳才對(cost比pulsed低....)
2.When benzene molecules are dissolved in ethanol at 25ºC, its fluorescence
lifetime is 31 ns and the fluorescence quantum yield is 0.04.
Question:To measure the fluorescence lifetime of 31ns, what would be the proper
modulation frequency (Hz) range, if the frequency-domain time-resolved fluorescence spectroscopy
is used?
感覺沒有modulation(M)跟 phase-shift(Phi) 無法計算 range
是我用錯公式嗎?
請大家指導,謝謝
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 220.136.32.132
※ 文章網址: https://webptt.com/m.aspx?n=bbs/Physics/M.1492963265.A.87A.html
1F：→ hank780420: 第一個剛好最近聽過相關的talk multi-photon需要非常 04/24 00:03
2F：→ hank780420: 高的光子通量才有機會發生 連續跟脈衝就算功率差不多 04/24 00:03
3F：→ hank780420: 脈衝那一瞬間的光子量遠遠超過一般連續的雷射 04/24 00:04
4F：推 youzi1114: 其實要比的就是瞬間功率，連續光瞬間功率等於平均功率 04/24 23:32
5F：→ youzi1114: ，脈衝則是平均功率除重復率(變能量)再除脈寬 04/24 23:32
6F：→ luben: 請問重復率(變能量)有辦法計算嗎? 不然題目似乎沒有給.. 04/24 23:49
7F：→ ftsywind: 重覆率80MHz題目有給 04/25 12:57
8F：→ luben: 謝謝指導 想問第二題是否沒有phi角無法計算呢? 04/25 21:26
9F：→ shengwey: 31ns~5MHz linewidth. Whatever modulation scheme it' 04/26 23:39
10F：→ shengwey: s referring to should have a depth about 5MHz. 04/26 23:39