A high-resolution optical spectrograph for the Thirty Meter Telescope: design and performance

We have completed a conceptual design study of the High Resolution Optical Spectrograph for the Thirty Meter Telescope project. We propose the use of a fiber fed integral field unit and a dichroic tree to achieve R=100,000 spectroscopy from 310 to 1100 nm independent of AO performance. The system relies on the dichroic tree to provide coarse wavelength selection, and 32 first order spectrograph benches. This approach allows for simultaneous optimization of grating and detector performance for all wavelengths, resulting in high efficiency, near uniform dispersion, and reduced program risk and cost due to the high degree of component commonality. We present projected performance and design details.