The blue light in a ladder system: from double resonance optical pumping to Autler-Townes splitting Waseem Raja, Pijush K. Mandal, Vaishali Naik, Alok Chakrabarti and Ayan Ray Eur. Phys. J. D, 72 7 (2018) 123 Published online: 03 July 2018 DOI: 10.1140/epjd/e2018-90146-3