### Measure LI Curve and calculate threshhold current

li_sweepName="liSweep"; # sweep name


## Getting L-I curve results
li_myr=getsweepresult(li_sweepName,"laser power");
li_power=li_myr.getattribute(li_myr.getattribute);
li_current = li_myr.getparameter(li_myr.getparameter);
plot(li_current,li_power,"Current [A]","Optical Power [W]", "L-I Curve");
legend("LI Curve");
li_numpts = length(li_current);

## Calculating slope of the L-I curve
li_slope = matrix(li_numpts,1);
li_slope(1) = ( li_power(2) - li_power(1) )/(li_current(2) - li_current(1)) ;
for (li_i=2:li_numpts-1) {
   li_slope(li_i) = ( li_power(li_i+1) - li_power(li_i-1) )/ (li_current(li_i+1) -li_current(li_i-1));
}
li_slope(li_numpts) = (li_power(li_numpts) - li_power(li_numpts-1) )/(li_current(li_numpts) - li_current(li_numpts-1));


## Calculating second derivative of the L-I curve
li_dslope = matrix(li_numpts,1);
li_dslope(1) = ( li_slope(2) - li_slope(1) )/(li_current(2) - li_current(1));

for (li_i=2:li_numpts-1) {
   li_dslope(li_i) = ( li_slope(li_i+1) - li_slope(li_i-1) )/ (li_current(li_i+1) -li_current(li_i-1));
}
li_dslope(li_numpts) = ( li_slope(li_numpts) - li_slope(li_numpts-1) )/(li_current(li_numpts) - li_current(li_numpts-1));

## CalculatingtThreshold current
li_kth = find(li_dslope,max(li_dslope));
li_thresholdcurrent = li_current(li_kth);
?"threshold current = " + num2str(li_thresholdcurrent);


##Save data 
li_out=struct;
li_out.name = currentscriptname; 
li_out.thresholdcurrent = li_thresholdcurrent;
li_out.thresholdcurrentindex = li_kth;
li_out.current=li_current;