Not so much rotor technology but more powerful engines that allow smaller rotor discs and make them work harder, producing the higher downwash speeds.
S92 - rotor 56'4", 2 x 2520 SHP engines, MTOW 26,150 lbs
AW 189 - rotor 48', 2 x 2000 shp engines, MTOW 18,300 lbs
Sea King - rotor 62', 2 x 1660 shp engines, MTOW 21, 400 lbs