IOM 2020, Експеримент — Задача 15
Answer Sheet
Внимание: Бележка към темата
The source is the experimental-round answer sheet with the official answers overlaid in red; the task description with the experiment setup (videos) is not in the archive, and the answer-sheet pictures are available only with the answers drawn on them.
Условие
Q.15 a) What function of the power of the first harmonic should be proportional to the power of the third harmonic theoretically? Write down the formula.
Q.15 b) What function of the second harmonic power should be proportional to the third harmonic power theoretically? Write down the formula.
Q.15 c) The dependence of the third harmonic power on the first harmonic power or the second harmonic power can be expressed as follows, or
From the experimental data, calculate the power to which you need to raise the power of the first harmonic to get a result proportional to the power of the third harmonic. Also calculate the proportionality factor .
Q.15 d) From the experimental data, calculate the power B to which you need to raise the power of the second harmonic to get a result proportional to the power of the third harmonic. Also calculate the proportionality factor A.
Q.15 e) Briefly describe the reason why the experimental dependences of the third harmonic power on the first and second harmonics power do not coincide with the theoretical ones. Write down the answer in English.
Отговори
- Q.15 a)
- Q.15 b)
- Q.15 c) B = 2.38, 2 < B < 3
- Q.15 d) B = 1.2, 1 < B < 1.5
- Q.15 e) The filter transmits radiation of the fundamental and second harmonics.
Решение
Answer 15 a) Cubic dependence
Answer 15 b) Degree «one and a half»
Answer 15 c)
for
The main thing is that B is less than 3, but more than 2
Answer 15 d)
The main thing is that B is less than 1.5, but more than 1
for
Построить зависимости в двойном логарифмическом масштабе. Провести линию (т.е. выявить наклон) и вычислить степень. Учитывая неточность построений. Величины коэффициентов A не так важны. Важен порядок величины. См. дополнительные листы.
Answer 15 e) The video showed that when we remove the crystal for 3w, then a signal remains on the photodetector 3. When we close 3 FP, then the signal is less, when we open, then more. This means that either w or 2w radiation passes through the filter, which should be absorbed.
The filter transmits radiation of the fundamental and second harmonics.
Additional forms 3
Third harmonic versus first. B = 2.38

Third harmonic versus second. B = 1.2

Experimental data for second harmonic generation.
| KDP 0.5 cm | KDP 2.0 cm | KDP 4.0 cm | |||
|---|---|---|---|---|---|
| First harmonic Power, Watts | Second harmonic Power, Watts | First harmonic Power, Watts | Second harmonic Power, Watts | First harmonic Power, Watts | Second harmonic Power, Watts |
| 11040 | 0.801 | 6662 | 3.725 | 3413 | 1.902 |
| 20850 | 2.517 | 20170 | 35.31 | 5990 | 5.867 |
| 40230 | 10.111 | 36980 | 126.1 | 12580 | 26.88 |
| 74900 | 32.14 | 64740 | 390.2 | 22940 | 84.08 |
| 93200 | 54.09 | 82900 | 569 | 37210 | 240.2 |
| 126800 | 97.89 | 108400 | 1050 | 54780 | 565.9 |
| 147200 | 131.1 | 127400 | 1387 | 81350 | 1157 |
| 165100 | 169.7 | 151200 | 1977 | 97730 | 1574 |
| 171700 | 184.2 | 167400 | 2388 | 116300 | 2319 |
| 177500 | 2697 | 138000 | 3224 | ||
| 153000 | 4127 | ||||
| 155400 | 4331 |
Experimental data for third harmonic generation.
| First harmonic Power, Watts | Third harmonic Power, Watts | Second harmonic Power, Watts | Third harmonic Power, Watts |
|---|---|---|---|
| 7768 | 0.4 | 147 | 9.01 |
| 12950 | 1.5 | 432.8 | 30.13 |
| 26010 | 9.2 | 667.8 | 51.41 |
| 40890 | 30.77 | 1384 | 123.9 |
| 58310 | 70.1 | 2182 | 217.3 |
| 76790 | 110.9 | 3000 | 318.9 |
| 98830 | 210 | 4546 | 557 |
| 117900 | 265.5 | 4913 | 577.8 |
| 137000 | 412.9 | 5550 | 678.3 |
| 154600 | 502.8 | ||
| 162900 | 685.1 | ||
| 166200 | 676.7 |
Оригинал в Архива: exp.pdf