function x=manualbeam(M,guess)
    x=lsqcurvefit(@gsbeam,guess,M(:,2),M(:,3)-M(:,4));
    figure
    hold
    grid on
    xlabel('Stage Translation (mm)')
    ylabel('Photodetector Output (V)')
    text(0.8,0.2,['A = ' num2str(x(1))],'FontSize',12,'Interpreter','none','Units','normalized');
    text(0.8,0.15,['x0 = ' num2str(x(2))],'FontSize',12,'Interpreter','none','Units','normalized');
    text(0.8,0.1,['w = ' num2str(x(3))],'FontSize',12,'Interpreter','none','Units','normalized');
    title('Gaussian Fit to Beam Data: Fit Curves and Data')
    xp=min(M(:,2)-1):.1:(max(M(:,2)+1));
    yp=gsbeam(x,xp);
    plot(xp,yp,'Color',[1 0 0]);
    scatter(M(:,2),(M(:,3)-M(:,4)))
    orient landscape
    hold