Q1} We often use laser diodes to excite biological samples and observe their fluorescence emission. Figure 1 shows a transfer function (the laser output power P vs the driving current I) of a laser diode, where you can see that a typical laser has three different operation regions (taking the transfer curve at 0oC as an example): i) Sub-threshold: the laser operates below the threshold current, Ith, emitting minimal light. ii) Linear region (this is where the laser usually operates): the driving current is higher than the threshold, the laser shows the best efficiency. iii) Saturation: the driving current is too large, and the efficiency drops again (note the behaviour in this region is not linear, but let’s approximate it with a straight line for simplicity). We also notice that the transfer function is sensitive to the temperature. The threshold current Ith is also a function of the temperature. 1.1 What are the threshold currents of the laser for 25 and 100 oC? (2, 2 marks) 1.2 What are the transfer gains (we also name the transfer gain as ‘sensitivity’ DP/DI) of the laser operating at the linear region, for 0, 25, and 100 oC, respectively? What is your observation (2, 2, 2, 3 marks) 1.3 From Question 1.2, what are the laser diode’s linear dynamic ranges (both I and P) for 0, 25, and 100 oC, respectively? (6 marks) 1.4 Suppose the fluorescence experiments require the laser diode to deliver a modulated laser power between Pmin = 1 mW and Pmax = 6 mW. What is the driving current range for 0, 25, and 100 oC, respectively? (6 marks) Instructions: Plagiarism free Solutions generated from any AI platform is strictly Prohibited Referencing and formatting Style APA Need Typed Solutions only.

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Q1} We often use laser diodes to excite biological samples and observe their fluorescence emission. Figure 1 shows a transfer function (the laser output power P vs the driving current I) of a laser diode, where you can see that a typical laser has three different operation regions (taking the transfer curve at 0oC as a