Setup used to determine diffraction efficiency in a single-pass configuration. A laser driver powers a wavelength-tunable laser diode which feeds light into a single-mode (SM) fiber. The fiber is connected to two attenuators, of which one is tunable. These attenuators ensure that the detector is not saturated within reasonable integration times. After the attenuators, light is injected and sent through a 50/50 beamsplitter. The reflected component is sent into a spectrum analyzer which allows for constant monitoring of the wavelength sent out by the tunable laser. The transmitted component is collimated by a 40cm off-axis parabola (focal length: 2580 mm). A linear polarizer and iris form the entrance pupil of the grating measurement setup. The collimated beam can be sent through the VPH or reflected by a plane mirror. A secondary plane fold mirror and a doublet form the camera of the system and focus light on a photodiode which allows for power measurement.