Subsection (1) of section 4 of Chapter 32 of the General Laws, as appearing in the 2014 Official Edition, is hereby amended by inserting after paragraph (s) the following paragraph: --

(t) Any faculty member or professional employee of any public institution of higher education who is a member of the state employees retirement system and who has received or receives a leave or leaves of absence without pay approved by the employing institution to accept a prestigious award, fellowship, scholarship or other special assignment opportunity that benefits both the individual and the employing institution of public higher education, may, before any retirement becomes effective, establish up to two years of such service as creditable service for the purpose of determining his retirement allowance pursuant to the provisions of paragraph (a) of subdivision (2) of section 5 of Chapter 32.  Eligibility for said creditable service shall be conditioned upon payment into the annuity savings fund of the state employees retirement system of an amount equal to the contributions he would have otherwise paid into the retirement system for said period or periods of service based upon the salary he was receiving prior to the commencement of his leave or leaves of absence together with regular interest thereon.  Such payment shall be made in one sum or installments as the state board of retirement shall prescribe.