ORIGIN software can do it, once you have the data. Unless you want to have not the software alone but a combination of a specialized hardware with a built-in software..Why are not happy with a lock-in?

Thank you Serge,

Actually we don,t have lock-in ample-fire. We are using the peak detectors associated with NI card. Present I am facing the two problem signal conditioning response and dynamic range.

I used DAQ from NI with Si detector for measuring SHG from Au films when exciting it with Ti:Sapph. In order to select the optimum range we wrote an add-app in LABVIEW that would change the scale automatically. Because of high rep rate from the laser, it was a quazi-cw regime so lock-in wasn't required.

Dear Sudhakar,

I suggest you tune a bit the question as the lock-in amplifier is only relevant in the handling of low signal to noise ratio and not very useful when your amplitudes are significant.

I guess you should clarify why you need a fast detector, in general Z-scan are quite slow.

Let us know.

Best

MArco

Dear Marco,

Thanks for your comments.

Here fast detector means not the signal light detecting detector. I am using a photo diode for detecting the signal. This detector connected to the NI card through the peak detector (signal condition). Now peak detector response is impotent. That is depend upon the OP amp used in peak detector circuit. Earlier we used signal condition circuit with OP amp 3140E. This circuit will slow response. In the sense, when I block and unblock the light its not immediately going low and high amplitudes. Its taking some 2 to 3 steps. Here, saturation level of signal conditioning circuit also impotent. So, I want some commercial peak detector with fast response and good dynamic range (minimum and maximum range).

Oh, yes! Some OP Amps are notoriously slow for sure. Can't you just use a different one instead? You may also consider matching the load resistance to make sure that you have shortest RC-constant.

Yes Serge, we are using different one. That is much faster and nice one. The problem is dynamic range. Some of organic samples with more signal this one creating the saturation problems. So any of scientific electronic device providers can consider these two problems if they can invent new device it is better for these experiments. I don`t know it is already available in the market or not.

Dear Sudhakar

I once used a fast resettable peak-and-hold (also called pulse stretcher ) module from ANALOG MODULES, to detect pulses in a z-scan setup (J. Opt A Pure Appl Opt, vol 4, pag 404, ( 2002), let me know if I should send the paper) . It was fairly linear, and in any case its response could be calibrated to linearize it.  Moreover the gating and reset capabilities were very useful

Thanks, Mauro

I tried for this journal. But we don,t have access here. Can you please send this article.

Please find the paper attached. The pulse stretcher was model 611 from ANALOG MODULES:

Thanks, Mauro....