The invention provides a height detecting apparatus for a lithographic apparatus. Each photovoltaic component includes an optical nano-antenna exhibiting an electromagnetic resonance in a first resonant spectral band, at least one lateral dimension of the optical nano-antenna being subwavelength in size, and a spectral conversion layer allowing at least part of the solar spectrum to be converted to said first resonant spectral band. For example, the extrusion temperature and shear rate employed during melt blending are relatively low to help limit polypeptide dissociation, thereby minimizing the impact of aggregation and embrittlement. The ends of the conductors are terminated at a single plug for insertion into a receptacle. The network includes a database storing the call management profile, a server in communication with the database for generating an interface document including the call management profile, and an AIN in communication with the server.