General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We have designed and built a low-temperature ͑1.3-4.2 K͒ scanning-tunneling microscope which is capable of collecting light that is generated in the tunneling region. Light collection is done by means of two fibers whose cleaved front is in close proximity (Ϸ1 mm͒ to the tunneling region. The whole system can be operated in high magnetic fields ͑11 T͒ without loss of optical signal strength. As a demonstration, we measured the electroluminescence spectra of an InGaAs quantum well at various temperatures. At 4.2 K, we found an electron-to-photon conversion factor that is three orders of magnitude higher than at room temperature.

We describe the design and performance of a low temperature (1.3–4.2 K) scanning tunneling microscope (STM) setup that can be used in magnetic fields up to 9.5 T. Due to the compact, rigid, and concentric design, the STM is very insensitive to external vibrations. The influence of external magnetic fields on the performance of the STM has been minimized by making a version completely out of titanium (instead of stainless steel). The STM routinely shows atomic resolution on various samples over the whole magnetic field range. We demonstrate the spectroscopic capability by local spectroscopy of the Abrikosov flux lattice on NbSe2.