THz 计算器
Five analysis tools and four conversions that come up in every terahertz experiment. Everything runs in your browser; nothing is sent anywhere.
厚度分析
拖入一段时域扫描，即可读出样品厚度与折射率。当内部回波可分辨时，两者同时求解 — 无需假定折射率，也无需标定样品。全部在浏览器中运行，数据不会发送到任何地方。
打开工具 →涂层厚度分析
通过一次反射扫描获得汽车漆层中的每一道涂层——清漆、色漆、底漆、电泳层。它们的回波在脉冲内部相互重叠，因此一次性拟合整条波形。并告诉您哪些涂层真实存在。
打开工具 →Terahertz transmission
A reference scan and a sample scan in, transmission out. Both transformed, the spectra drawn against the noise floor so you can see where the data ends, and refractive index and absorption from a thickness. Linear, per cent, log or dB.
打开工具 →Organic crystal phase matching
What thickness of DAST, DSTMS, OH1 or BNA gives the most terahertz, and where the band ends. Coherence length, the phonon, and output against thickness, from indices you can replace with your own measurements.
打开工具 →EO 探测带宽
GaP 或 ZnTe 电光探测器实际能给出多少带宽。选择晶体、厚度、探测光波长与脉冲宽度；曲线显示速度失配与声子在何处截断响应。
打开工具 →光谱单位换算器
TDS 扫描范围 ↔ 分辨率
频率分辨率由时域波形的长度决定：Δf = 1/T。
PCA Scanner：基本型 600 ps / < 2 GHz，选配 3 ns / < 0.5 GHz。
衍射极限光斑
d = 1.22 λ f / D.
RIGI 视场
焦平面阵列的有效面积，不含物镜。
应用笔记
What these tools are doing, and where each method quietly gives a wrong answer.
Refractive index and absorption from a THz-TDS measurement
How the standard thick-slab extraction works, what it assumes, and the four places it quietly gives you a wrong answer: etalons, phase unwrapping.
Read it →Choosing an electro-optic crystal for a target bandwidth
GaP, ZnTe, GaSe and BBO compared honestly. Why velocity mismatch, not material quality, sets your detection bandwidth.
Read it →Organic crystal thickness: why thicker stops helping
DAST, DSTMS, OH1 and BNA. Coherence length, terahertz absorption and pump absorption each cap the useful thickness.
Read it →Dynamic range, and where your data stops being data
Bandwidth claims mean nothing without a dynamic range to go with them. How to measure the noise floor honestly.
Read it →Water vapour lines and what they do to a transmission spectrum
Why atmospheric absorption lines throw spikes into a transmission ratio, why purging is the real fix.
Read it →