  We report on the generation of 500 mW of spectrally pure laser light at the
460.86 nm transition used for laser cooling of strontium atoms. To this end we
inject a high power single mode laser diode with light from a stabilized
extended cavity diode laser. To optimize and monitor the injection status and
the spectral purity of the slave diode we developed a novel technique that uses
a single passive optical element. A narrow band interference filter generates a
suitable monitoring signal without any additional electronics for post
processing of the data. Our method greatly simplifies the daily operation of
injection locked laser diodes and can be easily adapted to other wavelengths of
interest.
